Perry's Perennial Pages

Frequently Asked Questions (FAQs) on Perennials

Dr. Leonard Perry, Extension Professor, University of Vermont


The following topics and tips on herbaceous perennials are addressed below: What plant and where? Care and Culture, What's Wrong? General. Click on questions to go directly to answers, or you may scroll through all. At the beginning are the latest additions, as well as tips of interest.  

Can't find your answer?  Then if you have certain browsers such as Mozilla Firefox or Explorer, go to Edit>Find in Page at the top and type in keywords for what you are searching.  Still can't find your answer?  Then go to the resources at the bottom of the page.

Latest Additions  2/14/13

How do I prevent Genista Broom Moth Caterpillars from defoliating Baptisia australis?  Ann D, PA
The caterpillars are very unique looking and they are easy to identify as genista broom moth caterpillars (Uresiphita reversalis). Although more common in the southwest, especially Texas, they are known to exist from Nova Scotia to Florida, west to California and north to the Midwest. In 2012, a widespread outbreak was reported in Connecticut, Maryland, Ohio and Tennessee. The defoliated plants reported were mainly Baptisia, but others reported were all in the pea family. They can completely defoliate plants.  Control options include:
- check frequently in early spring for egg masses and remove them. The eggs are on the leaves, cream to yellow color, and although difficult to see, should be visible.
- hand pick for a light infestation.
- use insecticidal soap if the first two steps do not work. This will suffocate the caterpillars while they are still small in size.
- use labelled insecticides if the above three steps do not work. A least toxic choice might be Bt  var. kurstaki. (answer originally from Ann D, in PSS123 course)

Latest tips
*(on deerproofing, from a gardener in Canada): I've had good luck with just sprinkling the plants directly with cayenne or hot chili spice.  Also I drape plants with cilantro, lavender and yarrow.  Deer wont eat anything with those on them.
*The latest on bug zappers, and why you shouldn't use them (from Entomological News, 107(2):77-82)
"Our survey of insects electrocuted during routine use of electric insect traps revealed only 31 biting flies, a minute proportion (0.22%) of the 13,789 total insects counted.  In contrast, species from 12 orders and more than 104 nontarget insect families, including 1,868 predators and parasites (13.5%) and 6,670 nonbiting aquatic insects (48.4%) were destroyed.  The heavy toll on nontarget insects and the near absence of biting flies in catches suggests that electric insect traps are worthless for biting fly reduction - and probably are counterproductive - to homeowners and other consumers."

*One gardener sent me this website (you'll need adobe acrobat to read it: http://www.cfr.washington.edu/research.mulch/myths/hydrogels.pdf), which warns of potential problems using hydrogels-- those water absorbing materials which are claimed to reduce watering in container mixes.  (Iowa)
 

What plant and where?
*Will perennials that grow well in sun also grow in shade? (VT)

*I have heard of hollyhocks referred to as both biennial and perennial. Does this have more to do with the type of hollyhock or the growing conditions? (VT)

*Can you recommend a perennial ID/guide/source book or website?  I need to ID a few plants (photos needed).  If plants were organized by sun / shade / leaf color that would also be helpful. (VT)
*I would like to know if you know of any reference book about perennial plants that included information concerning their wind tolerance. (NY)
*Why does a garden with too much variety not seem as complete as one with a set theme? And how can I keep this variety but give my garden/landscape a more solid look? (VT)
*What perennial or shrub would be suitable for planting with the use of cremation ashes?  (mid-Atlantic)

*We are looking for a grass to plant like a hedge along the driveway.  Any suggestions?  (Maine)
*I want to use drought-tolerant grasses to minimize upkeep but don't know what to plant next to the neighbour's cedar hedge which seems to suck the life out of my  garden, which has full sun for most of day. (Toronto) *I grow plants from seeds under lights.  My columbine have aphids.  Where do they come from?  (Vermont)
*How can I grow root-invasive perennials such as mint in the garden? (VT)
*Are there tall grasses or flowers, even vines, I could plant on top of a septic leach field to hide a fence also on top of the field?  (NY)
*I am looking for a tall fast growing grass to provide coverage next to a busy road that will stand up in the winter too.  Do you have any suggestions?  (MN)
*Are the blue lupines seen in June in fields all over northern New Hampshire and Maine the native lupine perennis or are they escaped non-native garden plants?  Any good suggestions for blue native flowers we can plant? (New Hampshire)
*What kinds of plants can be planted along a non-spring-fed pond to help keep it clean? This is a large pond , over an acre, and I understand that cattails and other plants will help filter the pond water. (Vermont)
*Can I plant hostas under a maple tree? (Illinois)
*Do  you have any tips for creating a winter garden or caring for a winter garden in Southern Cal? (California)
*Can you suggest the best perennials for a seaside garden in northern California, about 1 mile from the ocean on a high peak.  There's nothing between my yard and the Pacific Ocean. It is quite windy and often damp throughout the summer due to heavy fog.  (northern California)
* I have a large zone under pine trees.  I would love to have a shade garden there but have heard that it is difficult to get anything but fern to grow in the shadow of pines.  Do you have any suggestions? (Michigan)
*I have a plant which was sold as "ghost plant."   I have grown it in my garden and it has white plumes something like astilbe but it is about 5 feet tall.  Can you tell me what I have and whether or not it will perform in dense or filtered shade? (Illinois)
*I'd like a list of new perennials for this year, ones that need to be better known.  (Pennsylvania)
*I'd like to plant some heather, do they need full sun or will they take part shade? (New York)
*Could you recommend some perennials for part shade, under a drip line of a roof?  (New Hampshire)
*What are some plants I can use to attract hummingbirds to my garden?  (Maine)
*Is there such a thing as a perennial that will flower throughout the summer?  Shady and sunny areas. (Kentucky)
*What are some groundcover herbaceous perennials that would be salt tolerant?  (Vermont)
*I need suggestions for Zone 5 groundcovers that will provide weed and erosion control on a slope in full sun. The soil has a mostly clay content and surrounds a pond. (upstate New York)
*I want to find a list of perennials suitable for containers.  (Germany)
*What is your favorite perennial? (Iowa)
*There is a dense shade area by a corner of the house with no sun.  Hard to find something to grow here.  Hostas and hydrangea do OK.  I would like something else, but have had no luck.  Could it be the soil? (Ohio)
*I have a retaining wall with springs keeping the soil damp in front of the wall. What are some good choices for a shady, moist soil ground cover? I have had luck with ferns.  (New York)
*What makes 'Blue Fortune' Anise Hyssop (Agastache) better than other cultivars?
* What would be a good perennial groundcover for wet soil and sunny? (Ohio)
*What are some perennials I can plant that will take drought like we've been having this year? (Massachusetts)
*Where can I find whether plant ??? is hardy in my area?
*I am new to the area (any area, I've gotten this question from Alabama, Arkansas and Massachusetts among others) and want to know what to plant, what will grow well, and some designs.
*My lawn has several birch trees and the grass has turned to moss. I would like to gradually replace the grass with flowers and ground cover. Not too expensively and I would like to do the work myself. I am a new gardener. (St. John's, Newfoundland)
*I'm new to growing perennials, and wondered if there is a good book on color to help me design with them? (Massachusetts)

 

Care and Culture
* Can you give people advice on how to remove their invasive seed producing plants/shrubs in a proper manner? (VT)

*How can I effectively control sucker growth on rose bushes? (PA)
* My daffodil and tulip bulbs don't bloom. They have plenty of healthy leaves but no blooms.  What fertilizer should I use to produce blooms? (VA)
*A friend of mine is going to give me some bulbs that she says are "sprouting" and in pots.  Can they still be planted outside now? Shouldn't they be planted in the Fall? Would I let them go dormant and plant in Fall?  Will they live if I plant them in the ground now?  (VT)
*I am planning on plant a small batch of Salvia May Night (Salvia sylvestris ‘Mainacht’) this year in one of the garden beds on the side of my parents’ house. If I treated it like annual Salvia and pinched back the dead flower blooms, would this promote more flowers? (VT)
*What is the ideal fertilizer ratio for Brugmansia aurea?  (CA)
* Is it possible to overwinter English roses in cold climates?  (VT)
*I am interested in replanting an Easter lily and Oriental lily into my garden.  Will they bloom for the summer?  The Easter lily already bloomed and the Oriental lily is blooming now (late April).  (Illinois)
*How can I maintain smaller rounded habit of Sedum 'Autumn Joy' and Coreopsis 'Moonbeam'.  They are 4-5 years old.  (Pennsylvania)
*I planted some summer daffodils this year.  Do I have to dig them up over winter?  (Vermont)
* This time of year (early March) leaves on our hellebores are ugly and detract from the emerging flowers.  Can we cut them off without causing harm to the plant?  (NC)
*We've tried starting gladiolus indoors from small bulblets we collected last year.  It has been 6 weeks with no signs of growth.  Any tips or clues? (WI)
*You mention to make late-blooming perennials such as asters and Helen's flower shorter and more bushy to cut back by a third.  Is this a third overall from the top down, or thin out a third of the shoots?  (Vermont)
*Is it better to water daily when plants are in the sun or to water once a week? (Connecticut)
*We have lots of woodashes.  Can these be put on the garden without harming it?  (Massachusetts)
*When and how do you divide peonies?  (Michigan)
*I have retrieved some Stella d'Oro daylily seeds from my son's very successful plants.  Now what do I do to propagate them? (Illinois)
*I have several coreopsis plants.  Should I cut off the dead blossoms, and if so, where do I make the cuts? (New York)
*I will be moving from in September. I have 3 favorite perennials including hosta and peony I would like to take with me. What is the best way to transport them. (Ohio)
*I recently bought a Concord Grape spiderwort.  You mention in your article to cut back after bloom when the foliage gets ratty.  Mine has reached the ratty stage and my question is how far back should I cut it? (Vermont)
*Can I use horse manure mixed with wood shavings in the garden?  (Vermont)
*Books say to cut lavender back in the spring, but we live in a cold zone in Vermont and never do.  Should we?  (Vermont)
*If I bring primrose in to give as Christmas presents, what do I tell people about their care?  (Toronto)
*It's fall and I am moving and want to take my perennials with me to my new house, how do I do this without harming them? Do I plant them outside or in pots? (Indiana)
*What are some organic methods of controlling insects and diseases on herbaceous garden plants? (New York state)
*I'd like to make some cuttings of perennials, how do I go about this?  (Vermont)
*I have some small perennials in pots in a hobby greenhouse.  How should I treat them so they will get cold and bloom next season? (Toronto)
*How do I improve heavy clay soil?  (Delaware)
*Does the last time I can plant perennials depend on how hardy they are?  (Vermont)
*We would like to sow seeds from a hosta, and don't know how, or what the seeds are.  Please advise.  (Vermont)
*I have purple siberian iris, with what appear to be seedpods and layers of seeds inside.  Is this correct, and will this take away from next year's blooms? (New York)
*I have 'Jacob Cline' bee balm and I would like to propagate them. What is the best way? (Pennsylvania)
*Will bulbs grow up through a layer of mulch, or do I have to open up space for them?  (Vermont)
*Can annuals and tender perennials be overwintered indoors?  (Vermont)
*Our Elijah Blue fescue has gone to seed. Do we need to remove the brown seed stems or leave them on? (Wyoming)
*I would like to know some good, environmentally friendly ways to clear out large grassy areas (acres)
to replace with wild flower seeds.  (Massachusetts)
*Are antidessicants effective? (New York)
*I am trying to grow rugosa roses from seed. Didn't work last year.  Any suggestions? (Maine)
* I received a potted tulip as a gift. Is there a way to have the bulb bloom again, what is the procedure? (Mexico)
*With all this warm weather this fall, my perennials are starting to sprout and green up.  Should I mulch them, or leave alone? (New York)
*compost tip
*I'd like to know when a plant is done blooming for the year, like a lily ....can you cut it down or should you leave it till it dies off ? (Wisconsin)
*Three years ago I was given a well established peony dug up from a friends garden.  Last year was the first time it bloomed for me - this year, only one flower - the plant is very lush, dark green and about 3' accross by 3.5' high (no sign of disease).  I give it a light organic fertilizer once a year and lime it at least once a year. It gets about 4.5 hrs of direct sun during the middle of the day - what can I do to improve bloom on this peony? (Vermont)
*Two articles from two different Extension Service offices state that most perennials do well in pH of 6.6 -7.0.  Another states they generally do best in 5.5-6.5. Can you put this issue to rest? (Massachusetts)
*We recently had a devastating hail storm which destroyed all of our plants. What is the best way to care for plants which have been beaten down is such a manor? Should I cut them back? If so how much?  (North Dakota)
*I wanted to know if I have to cut back my Purple Allium flowers?  They are huge, and I don't want to cut off the tops if I am not supposed to.  (Utah)
*What can I expect from my Baptisia plant the first year (it didn't bloom), and how do I prepare it for winter? (Masschusetts)
*How can I overwinter tender perennials? (Toronto, Canada)
*This season my wooden stakes rotted. Is there anything better to use? (Vermont)
*Do you know what varieties of lotus might survive moderately cold Dutch winters? (Netherlands)
*I'm a new gardener and would like to grow some perennials from seeds. Which would you recommend? (Connecticut)
*I would like to grow Lenten Rose (Hellebore) from seeds to use as a groundcover for shade, since I can't afford to buy the expensive plants. How is this done? (Massachusetts)
*With the mild winter my daffodils starting coming up early this year. With the late snow and cold, will they be injured? (Vermont)
*How can I eradicate grasses that are growing among my spreading junipers? (Minnesota)
*How late can I plant perennials and bulbs? (several states including Alabama and New York)
*Should I cut back perennials in the fall?
*I didn't cut my perennials back in the fall. Is spring okay? (Ohio gardener)
*I didn't get my bulbs planted in the fall. Is early spring okay? (Illinois)
*Do you have any suggestions for how to keep up with the weeds? (New Jersey)

What's wrong? 

*How do I prevent Genista Broom Moth caterpillars from defoliating Baptisia australis?  Ann D, PA
*It appears we have a bad infestation of leaf minors on our columbine. What do you suggest to get rid of them?  Will the plants come back next year? Will the ground harbor these insects having them return next year? (VT)
*The stems and leaves on my garden phlox have turned white.  Not with mildew but the entire plant is a whitish yellow. What's happened? (CT)
* My daffodil and tulip bulbs don't bloom. They have plenty of healthy leaves but no blooms.  What fertilizer should I use to produce blooms? (VA)
*I just planted some day lilies a few days ago, went out this morning and the whole plant was uprooted and pulled a few feet away, what would do this - how can I avoid it again? (PA)
*Last year our peonies developed these awful looking red and brown spots all over them-it looked as though someone had set them on fire (the leaves at least).  What exactly is this, and how do you treat it?  (VT)
*Some of my daffodils this year overnight seemed to bend down.  What caused this?  (VT)
*I've heard putting beer in gardens traps slugs.  Does this really work, and why do slugs like beer?  (VT)
*I grow plants from seeds under lights.  My columbine under lights have aphids.  Where do they come from?  (Vermont)
*What causes my Stokes Asters to get black blotches on the leaves, along with big "bites" out of them?  (Vermont)
*I have hostas with twisted, stunted, and puckered leaves.  Is this normal, or a disease?  (Vermont)
*Are Japanese beetle traps a good control for these pests?  I've heard both yes and no. (Vermont)
*I have lily leaf beetles.  Is there anything I can do to the soil to control these beetles?  (Vermont)
*What perennials don't moles eat? (Virginia)
*I'd like to know what perennial summer flowers rabbits/squirrels won't eat? (Pennsylvania)
*I have a Final Touch daylily which has never bloomed.  I have had it for 3-4 years. (Oklahoma)
*I've been picking tons of asiatic garden beetles off my flowers.  Is there anything I can do? (Rhode Island)
* Since my black-eyed susans began to grow this spring, their tops look as if someone came along with a sharp instrument and cut them off.  They grow again, and the same thing occurs.  What is causing this problem? (New York)
*I have a problem with earwigs eating my flowers, especially hollyhocks, zinnias, and roses in bud. How can I control them safely, as I also have pets.  (Colorado)
*How do I control the Japanese beetles that devoured my roses this past season?  (Vermont)
*My daffodils and amaryllis are softy and mushy, with grubs eating inside.  I understand this is from the narcissus bulb fly.  What do I do for control? (Vermont)
*What product or process can I use to keep squirrels from digging up our bulbs after we plant them. (Wash.)
* I just planted black eyed susies about two months ago.  They were doing great, alot of blooms and then in a matter of two days, the leaves all turned brown and they are dying.  Nothing else I have planted there has done this.  What could be the problem.  (New York)
*I have about 1/4 acre of lawn invaded by the perennial bugleweed.  I do not have this in my garden, but think it came in with bark mulch.  What can I do to remove it permanently? (Vermont)
*Could you tell me whether deer eat daisies. I love daisys and recently moved near woods with a deer population. (New York)
*My daylilies have orange spots on the undersides of leaves and plants don't look good.  What should I do?  (various)
*This past year all my lily plants were devoured, buds, leaves even stems.  What caused this?  (New Hampshire)
*I can't seen to grow Black Eyed Susan in my yard - as soon as new sprouts come up they are eaten.  Any advice? (Connecticut)
*Why do petals of my black-eyed susies won't open up? The flowers look so wierd. They have large dark center but the yellow flower petals are like pointed needles. (Toronto)
*I found large grubs in bearded iris rhizomes when dividing them in late July.  What are they? (Vermont)
*I have a problem with neighborhood cats using my tulip beds for litter boxes and destroying bulbs with digging.  How can I prevent this?  I do not know the pet owners. (Michigan)
 *I was given a peony by someone who only had a blood red peony in her garden.  When I planted it, the color was light pink to fushia.  Is there anything i can do to get this color? (New Jersey)
* "Something" ate my Solomon Seals.  A rabbit?  Bugs? Creepy crawlies? What can I do? (Ohio)
*My primrose leaves are very limp and falling off, some have black leaves. Doesnt look like it needs water. It has fertilizer and food. What's wrong? (Alaska)
*My holly hock leaves are turning brown and withering. There is enough rain so dryness is not the problem.  what can I do to save them?  (Ontario)
*What effect will this year's drought (second worst in East on record) have on my perennials? (several states)
*Before my lilies bloomed the leaves and buds turned brown. They bloomed, but not well. Why? (Virginia)
*Something is eating my hosta leaves. What is it and what do I do? (Indiana)
*With all the rain from El Nino, what are the black spots on my leaves? (Los Angeles)
*How can I get rid of whiteflies? (Hamilton, Ontario)
*Why didn't my tulips bloom this past spring?
*What affect is this winter having on perennials?
*I have a serious problem with voles. I have tried many methods of ridding my garden of them while they continue ridding me of a garden. Any suggestions? (New Jersey--I get this question from all over, and have a problem myself in Vermont.)
*I have white disease on the leaves of my garden phlox, monarda and other plants. What can I do about this? (Pennsylvania)
*How can I keep stray cats from digging in my perennial garden? (Delaware)

General

*The third main ingredient shown on fertilizers is potassium.  What does Potassium do for plants? (NY)
*What amendments should I make to soil which has a high percentage of clay, becomes waterlogged and is slightly acidic? (PA)
*What is the benefit of placing Kelp Meal in soil?  (NY)
*What are the most common problems with soils that I should be aware of ? (VT) 
*What are the pro's of creating and maintaining a "mini-wetland" in my backyard?  (MA)
*I'm just getting into gardening.  What are ten of the most important items I should have? (VT)
*How do I keep the neighbors' cats out of my flower beds.  We've tried all kinds of repellents such as pepper, enzyme from the vet, and moth balls (which everyone suggested first).   When I put out moth balls the next morning I had three cats laying all over them.  They will go back into their own yard before we have time to get the water hose out. (TX)
*I have lots of yellowjackets around our yard which makes me uneasy gardening.  What can I do?  (Illinois)
*As a bride to be I am drying pink rose petals to use in my invitations.  I'm pressing them between sheets of paper in a heavy book, but find they are losing their colour.  Can you please offer me any advice as to how I can insure my next batch of rose petals keep their lovely strong bright pink colour? (London, UK)
*Local home improvement centers are now selling their perennials at half price (late fall)--is this a good bargin for zone 5? (Pennsylvania)
*I had a very unpleasant encounter with a euphorbia this summer, and I'm still bearing scars from the awful blisters.  Please send me information about the toxicity of euphorbias, as no big deal is made in most books.  They just explain that it is a skin irritant. I had to go to a physician's office! (Vermont)
*I have sandy soil, so my lawn and perennials have not fared well this year with the drought. What's the best solution? (Massachusetts, New Jersey)
*This year I had quite a problem with deer eating my perennials. What can I do, and are there any resistant plants? (upstate New York and others)
*Is there a good computer program to help pick plants and keep track of them? (Washington)
*What do you recommend as good labels for the perennial garden? (Virginia)
*Do you have any suggestions on where and how to buy good plants?
*I always have a problem keeping plants labeled. Do you have any suggestions?
*Is there a discussion list for perennials?
*When is the New England Flower Show?
*When is the Vermont Flower Show, and who is speaking? (New York)
*What is the provincial flower of Nunavut-- the new Canadian Province? (Ontario)
 

The Tips
*Bug Zappers (10/02): The latest on bug zappers, and why you shouldn't use them (from Entomological News, 107(2):77-82) "Our survey of insects electrocuted during routine use of electric insect traps revealed only 31 biting flies, a minute proportion (0.22%) of the 13,789 total insects counted.  In contrast, species from 12 orders and more than 104 nontarget insect families, including 1,868 predators and parasites (13.5%) and 6,670 nonbiting aquatic insects (48.4%) were destroyed.  The heavy toll on nontarget insects and the near absence of biting flies in catches suggests that electric insect traps are worthless for biting fly reduction - and probably are counterproductive - to homeowners and other consumers."

*Compost tip (9/01): a report released this month from Washington State University showed compost had been contaminated with the herbicide picloram.  This entered from animal bedding crops or manures from animals which had fed on crops treated with this chemical.  It latest for over a year, and through the composting process, with residual damage to desirable plants to which the compost had been applied.  The message: make sure your source of commercial compost if not organic is reliable, free of even lawn residues which may contain herbicides.

*Rabbits and Deer (5/02): In upstate NY I've found the best answer to rabbits, dear, cats, eating or digging is to sprinkle ordinary black pepper on plants, it doesn't dissolve and without stiff wind will deter for 2 weeks or so and it's dirt cheap. I've tried all the commercial remedies and this works the best!!!--Judi

*Hydrogels (6/02): One gardener sent me this website (you'll need adobe acrobat to read it: http://www.cfr.washington.edu/research.mulch/myths/hydrogels.pdf), which warns of potential problems using hydrogels-- those water absorbing materials which are claimed to reduce watering in container mixes.  (Iowa)

The Questions and Answers:

How do I prevent Genista Broom Moth Caterpillars from defoliating Baptisia australis?  Ann D, PA
The caterpillars are very unique looking and they are easy to identify as genista broom moth caterpillars (Uresiphita reversalis). Although more common in the southwest, especially Texas, they are known to exist from Nova Scotia to Florida, west to California and north to the Midwest. In 2012, a widespread outbreak was reported in Connecticut, Maryland, Ohio and Tennessee. The defoliated plants reported were mainly Baptisia, but others reported were all in the pea family. They can completely defoliate plants.  Control options include:
- check frequently in early spring for egg masses and remove them. The eggs are on the leaves, cream to yellow color, and although difficult to see, should be visible.
- hand pick for a light infestation.
- use insecticidal soap if the first two steps do not work. This will suffocate the caterpillars while they are still small in size.
- use labelled insecticides if the above three steps do not work. A least toxic choice might be Bt  var. kurstaki. (answer originally from Ann D, in PSS123 course)

*Will perennials that grow well in sun also grow in shade? (VT)

 Yes, many will grow in shade, or at least part shade (some that grow well in full sun in the north prefer this if a hot climate), BUT they may be more straggly, with weak stems, and often don't bloom as well if at all.  Also, some colored-leaved plants  may have more yellow or purple leaves in sun, with more green leaves in shade, needing more chlorophyll (the "green" key ingredient in leaves that helps them utilize sunlight). (both Q and A from Avery L as part of my PSS123 course)

 

*I have heard of hollyhocks referred to as both biennial and perennial. Does this have more to do with the type of hollyhock or the growing conditions? (VT)

Alcea rosea, the common hollyhock, is a biennial plant that flowers in the second year but may have one or two blossoms and plenty of leaves in the first year. The perennial rumors could come from the self-sowing characteristic of the plant New hollyhocks would sprout up in the third year without the gardener spreading more seeds. However, long bouts of dry heat, as well as rust and pests, could kill the plants before reseeding.  (both Q and A from Lindsay L as part of my PSS123 course

 

* Can you give people advice on how to remove their invasive seed producing plants/shrubs in a proper manner? (VT)

Invasive plants indeed have become a concern to gardeners, both root and seed invasive plants.  The first step of course is to be aware of what plants may become invasive before buying them, keeping in mind that invasive properties may depend in part on the climate and habitat (such as soils).  For existing plants, or ones that have become invasive through seeding already, easiest is to cut back before they go to seed.  If not many, they can be dealt with mechanically such as hoe or shovel.  For more resources and a list of plants, see the Vermont Exotic Invasive Plants website.  http://www.vtinvasiveplants.org/


*How can I effectively control sucker growth on rose bushes? (PA)
Root suckers, or  growth from the base of plants, are a notorious problem with rose bushes as well as some other plants such as lilacs and sumacs.  These shoots arise from roots, often at a distance from the plants, as the roots grow outwards.  Or, they may arise from the base of plants from below the graft union if plants are grafted or budded (as are most roses and many lilacs).  Often this suckering is unwanted, and in the case of grafted plants, will produce a plant different from the one purchased.  Control suckers by cutting them as close to the ground or root stock as possible.  Planting deeper than normal, such as with the graft union 4 to 6 inches below ground, also may help to prevent suckering. There are some products available on the market that inhibit sucker growth.  If applied to suckers shorter than 6" long they will prevent their growth for up to 3 months.  

*It appears we have a bad infestation of leaf minors on our columbine. What do you suggest to get rid of them?  Will the plants come back next year? Will the ground harbor these insects having them return next year? (VT)
Leafminers on columbine are a common problem, but luckily shouldn't affect plant health in the long term.  There are some insecticides you can use (check labels in your local garden store, preferably for organic solutions causing little harm to beneficial insects), but best control is to pick off infested leaves.  Check every few days beginning with bloom time which is when eggs are laid by leafminer flies and larvae then begin.  There are several generations per summer, so unfortunately you'll need to keep at it. Check each season beginning with bloom as these will likely return.  Also keep plants well watered and fertilized so they can better cope with this stress.  If only a plant or two, you might try erecting a small tent over plants just before bloom with a light-weight fabric as used for frosts.  This will keep the flies from laying eggs but the drawback is you don't get to enjoy the flowers!

*Can you recommend a perennial ID/guide/source book or website?  I need to ID a few plants (photos needed).  If plants were organized by sun / shade / leaf color that would also be helpful. (VT)

A great question, but unfortunately there is little for this on perennials, perhaps due to the great variety.  Lots of photos in books and online, but not really organized as you seek. There are several such references for wildflowers, with some overlap with garden perennials, but most are a-z with photos you just have to look through, one of better being: Armitage's Garden Perennials: A Color Encyclopedia.  Usually is recommended to ask a local expert gardener, extension office, or a local perennial nursery or complete garden center having trained professionals.

*I would like to know if you know of any reference book about perennial plants that included information concerning their wind tolerance. (NY)
I don't know of such a book or can't find such lists.  Basically for windy sites just consider more dwarf or compact and shorter selections (or serious staking).  Also you can prune taller late bloomers back by about half mid to late June to result in shorter and more compact plants.  Consider a windbreak from plants, fence, or a combination.

*The stems and leaves on my garden phlox have turned white.  Not with mildew but the entire plant is a whitish yellow. What's happened? (CT)
I think that still may be mildew, it often starts on bottoms of leaves turning the tops yellowish, undersides being whitish or grayish.  I'm not aware of other diseases causing this symptom, unless leaves are chlorotic from a soil problem like too wet, lack of fertility, or similar.


*A friend of mine is going to give me some bulbs that she says are "sprouting" and in pots.  Can they still be planted outside now? Shouldn't they be planted in the Fall? Would I let them go dormant and plant in Fall?  Will they live if I plant them in the ground now?  (VT)
Probably best to let them go on and bloom, die back naturally, then plant in the garden this fall.  Otherwise they may not be hardy to cold and frosts.  Having been "forced" they may not bloom well next year.  Keep in mind although most spring-flowering bulbs are perennial, many tulips are not so should be treated as annuals for a one-time show (unless you know they are perennial types). 

* My daffodil and tulip bulbs don't bloom. They have plenty of healthy leaves but no blooms.  What fertilizer should I use to produce blooms? (VA)
There are several reasons they may not bloom, probably not related to fertilizer.  Generally a top-dressing of most fertilizer, including organic ones, as bulbs emerge in the spring is sufficient.  Those specially formulated for bulbs are best.  Daffodils are usually fairly foolproof, the may reason they don't bloom is from lack of light--they and tulips really need full sun.  Yet in part to full shade, leaves wouldn't look as healthy or vigorous either.  Did you check to see if something ate the flowering stems as they emerged?  Don't cut leaves off bulbs after bloom, rather let them die back naturally, as they produce food for next year's bulbs.  Tulips, except for a few types such as the Darwins, are generally treated as annuals, with few blooms after the first year.  Considering your location, the bulbs might not be getting sufficient cold that is required to initiate flowers.  There are certain varieties of daffodils better for warm climates, and tulips often have to be "pre-cooled" (given artificial cold as in a refrigerator) to grow well in warm climates.  

*I just planted some day lilies a few days ago, went out this morning and the whole plant was uprooted and pulled a few feet away, what would do this - how can I avoid it again? (PA)
Did you use bone meal or an organic fertilizer?  Often these, even just disturbed soil, leads such mammals as racoons or skunks to think something is buried there so they dig, uprooting plants.  In high chipmunk areas of my own yard I have had to stop using organic fertilizer around perennials for this reason .  You could place pieces of wire mesh or screen around key plants until established to deter such digging.  There are many repellent products you can use on or around plants too, usually taste or smell deterrents, available at many garden supply stores.

*I am planning on plant a small batch of Salvia May Night (Salvia sylvestris ‘Mainacht’) this year in one of the garden beds on the side of my parents’ house. If I treated it like annual Salvia and pinched back the dead flower blooms, would this promote more flowers? (VT)
With the perennial version of Blue Sage, such as May Night, trimming back the plant 5-7 inches right when the flowers have faded promotes dense growth. It also increased to possibility of a second set of blooms at the end of the summer or in the fall. One could try pinching off the flowers spikes but it probably would not have the same effect.  (answer by Jonathon K)

*What is the ideal fertilizer ratio for Brugmansia aurea?  (CA)
Though the flowers are quite large they lack complete reproductive structures and therefor do not need very much phosphorus.  What they do need is a large amount of nitrogen, and potassium.  The potassium for more root growth, which is needed for better access to nutrients and water (as they need a lot) and the nitrogen for increaed vegatative growth.  The leaves are quite large, to provide enough carbohydrates for flower production.  A good fertilizer would thus be a combination of bone meal and bloodmeal.  (answer by Greg B)

*The third main ingredient shown on fertilizers is potassium.  What does Potassium do for plants? (NY)
Potassium is a macro nutrient necessary for plant growth.  Potassium is involved in more than 60 different enzyme systems.  One of the ways that plants use potassium is in the process of opening and closing their stomata.  Stomata are tiny pores that are found on the underside of the leaf.  They are responsible for gas exchange.  Plants grown in sandy, chalky, or peaty soils are more vulnerable to potassium deficiency.  Symptoms of potassium deficiency include, browning of leaf tips, yellowing of leaf veins, and purple spots on the undersides of the leaves.  (answer by Hayley Z)

*Last year our peonies developed these awful looking red and brown spots all over them-it looked as though someone had set them on fire (the leaves at least).  What exactly is this, and how do you treat it?  (VT)
This is most likely peony leaf blotch/measles/stem spot which is caused by a fungus Cladosporium paeoniae-they are red/brown to purplish brown on the leaves, especially at the leaf margins, and can even reach the upper stems of the plant, leaving raised spots.  For management-cut the stems at the ground level in the fall or early spring and rake the area.  Provide good air circulation (as this disease often comes as a result of the warm, humid weather), avoid wetting the leaves if watering.  Fungicides can also be used to help control the disease. (answer by Emma K)

* Is it possible to overwinter English roses in cold climates?  (VT)
Tender roses can be planted with the graft union 4-6 inches below the soil surface. This depth is reported to protect from cold winter climates while it still encourages adequate flowering in the summer.  Greater depth sometimes shows less success, but another rose authority says it may help in the coldest climates.   With this technique, the entire plant is pruned to ground level in the late spring if it isn't budding out,  being treated as an herbaceous perennial.  Planting at such depths encourages rooting of the stems and therefore survival of the plant should the root stock die out. The deep burying method discourages the root stock from throwing suckers. (answer by Wenda W)

*Some of my daffodils this year overnight seemed to bend down.  What caused this?  (VT)
This is likely due to frost damage or extreme cold, especially if they had started blooming before during a very warm period.  This should cause no lasting harm for future years.  Just make sure and add some bulb fertilizer around them now to help them make food and flowers for next spring's bloom.

*I've heard putting beer in gardens traps slugs.  Does this really work, and why do slugs like beer?  (VT)
Slugs are heavy foliage eaters that can be hard to spot during the day as they are nocturnal, hiding during the day and out feeding at night.  The damage they cause not only can kill the plant itself but can make the plant more vulnerable to disease or fungi.  Slugs are attracted to chemicals produced by many fermenting materials so traps using beer, sugar water or yeast mixtures can be put out to attract and subsequently drown the slug.  These traps need to be placed throughout the garden as their range is only a few feet and should be checked regularly to rid of the dead slugs and fresh liquid added. (answer by Kim C)

*Why does a garden with too much variety not seem as complete as one with a set theme? And how can I keep this variety but give my garden/landscape a more solid look?
(VT)
When a garden consists of large variety, but no repetition it will give the onlooker’s eye no where to begin. Therefore you’re not giving a common thread to tie your artwork together. If you are going to put work into something such as a flower bed, rock garden or entry garden, it’s beneficial to know how to make everything flow together nicely. And the key to making things flow, is coordinated repetition. Just a little extra time in rearranging your plants will allow you to keep the variety you want, but still make your design look complete. (answer by Bryn S)

*What amendments should I make to soil which has a high percentage of clay, becomes waterlogged and is slightly acidic? (PA)The best amendment to a clay soil is organic matter such as peat moss. Sand, the popular remedy, can actually act as a kind of filler into the large pores of loamy clay resulting in reduced porosity.  Peat moss has a lot of pores to hold important gasses for the roots of plants, has high moisture retentive capabilities, and provides nutrients and food for essential microbes. It also breaks down slowly, requiring less frequent applications. The only problem is that peat moss is acidic, and thus requires the use of lime to neutralize the pH of the soil. (answer by Dan C)

*What is the benefit of placing Kelp Meal in soil?  (NY)
Kelp meal serves as a natural source of many trace minerals, vitamins, hormones and plant growth regulators. Nutrients are supplied in a chelated form, which is the form of nutrients that are most easily taken up by plants and least likely to be made unavailable by chemical processes occurring in the soil. It has been used for centuries as a soil amendment that increases soil nutrition and enhances plant growth. (Answer by David B)

*I am interested in  replanting an Easter lily and Oriental lily into my garden.  Will they bloom for the summer?  The Easter lily already bloomed and the Oriental lily is blooming now (late April).  (Illinois)
Once lilies have bloomed for the year, that is usually all for that year.  They need the season to build up food in the bulb for bloom the following year.  If they do bloom again in late summer or fall, it is often from other small offset bulbs they produce.  Since the Easter lily, and perhaps Oriental lily, were forced by growers into bloom outside their normal time, such bulbs often bloom during the summer the following year.  So I would plant into the garden, fertilize, and keep watered during dry spells.  You might cut off the very top of the stem where the blooms were if you see seeds forming, so the plant can put all the energy back into the bulb and not into producing seeds. 

*What are the pro's of creating and maintaining a "mini-wetland" in my backyard?  (Massachusetts)
Wetlands can filter excess pesticides and nutrients and provide homes for animals. A "mini wetland" (often called "rain garden")  is similar to a wetland and it may revamp your backyard to the state it was in before your community was built. A wetland will also store and clean runoff from your roof and house temporarily. The majority of plants that grow in such wetlands do not need standing water and can survive in semi-dry areas. Some herbaceous swamp plants include Blue Flag, Marsh Marigold, and Water Arum.

*I grow plants from seeds under lights.  My columbine have aphids.  Where do they come from?  (Vermont)
Aphids most usually come indoors from already infested plants from outside or purchased (so check all closely before buying, and after home for a few weeks for hatching insects).  They can come from eggs in soil (use a soilless bagged growing medium), fly in if winged adult aphids (keep windows screened), or hitch a ride in on clothes.  Since seedlings are tender, be careful if using pesticides that might harm the plants too.  First to try would be a dilute soapy water wash or spray from a spritzer.

*What causes my Stokes Asters to get black blotches on the leaves, along with big "bites" out of them?  (Vermont)

The leaf blotches are likely some form of leafspot that usually a lab has to culture to positively identify.  This plant usually doesn't have serious disease or pest problems, so I'm not sure what is causing the eating of the leaves.  It's best not to just spray a pesticide as you might be harming some beneficial insects as well.  Try and watch next season daily for pests as well as diseases, and collect any just as they begin, then take to a full service garden center or plant diagnostic lab for identification and control.  Hopefully these are a result of the weather this season, and may not appear next year.

*How can I maintain smaller rounded habit of Sedum 'Autumn Joy' and Coreopsis 'Moonbeam'.  They are 4-5 years old.  (Pennsylvania)
Often plants too tall or floppy are a sign of too little light.  Both of these plants in particular grow best in full sun.  Even then with age some plants, such as the Autumn Joy, may flop.  Plants that bloom late in the season such as Autumn Joy, Asters, or even tall garden phlox may be cut back by 1/3 to 1/2 in early summer.  This will result in shorter growth with more branching, and generally only slightly delayed bloom if at all.  This generally wont work with thin stems like on the Moonbeam.  Make sure this one has full sun, and not too much fertilizer or rich soil which can cause tall and floppy stems.

*I planted some summer daffodils this year.  Do I have to dig them up over winter?  (Vermont)
There really are no true daffodils that bloom in summer in the north, but this name is sometimes used for a South American relative of the spider lily which I think it resembles more than a daffodil.  Yes, either pot these up to bring inside over winter and keep barely moist in a cool location.  Alternately, you can dig the bulbs once the tops have died back from light frost, then store in moist peat moss in a plastic bag in a cool, non-freezing location.  Pot and begin watering in spring, or plant outside after chance of frost is past.

*I like the look of the boxwood-lined herb gardens but don't think boxwood grows too well in Vermont, or at least would take a lot of work to maintain. Any suggestions as to some kind of perennial that might be used instead to line a small herb and flower bed? (Vermont)
Depending on the microclimate on your property, such as a sheltered northern or eastern exposure, you might try one of the cultivars of Korean boxwood.  There aren't a lot of options for hardy perennials for the herb garden, chives being one I've seen used for edging.  Just make sure to keep flowers after bloom to prevent seeding.  Lavender can be used if a protected site such as in USDA hardiness zone 5. Most often I've seen the annuals holy basil or parsley, even lettuces, used.

*What perennial or shrub would be suitable for planting with the use of cremation ashes?  (mid-Atlantic)
Such ashes could be sprinkled around a planting, unless illegal as in some states.  In this case they could be used as fertilizer, similar to bone meal.  The latter often has an analysis of around 1-13-0, meaning it provides a little nitrogen, but mainly phosphorus, plus some calcium.  Buried in the soil at planting, this can serve as a slow-release phosphorus source.  However, if planting bulbs or small plants or perennials, you might also add some crushed shells or sharp pebbles to deter digging mammals attracted to the bone smell.  Since small amounts shouldn't affect soil pH or provide excessive nutrients, most plants should be amenable, the choice depending more on personal preference, light, and other site conditions.

*We are looking for a grass to plant along the driveway like a hedge.  Any suggestions?  (Maine)
If you want a tall grass (4-5ft), then consider one of the Switch grass (Panicum) cultivars.  Heavy Metal is bluish with reddish seed heads.  There are several other good blue cultivars, but Prairie Sky tends to flop.  Shenandoah is shorter, and more red.  Another group for a great upright effect of similar height is the Feather Reed Grass (Calamagrostis), Karl Foerster being a popular and good cultivar. If in a warmer climate you might consider Fountain Grass (Pennisetum), about 3ft. There are many good cultivars of Eulalia (Miscanthus), from 4 to 8ft.,  which with short and cooler seasons in the north do not tend to seed nor become invasive.

*I want to use grasses to minimize upkeep but don't know what to plant next to the neighbour's cedar hedge which seems to suck the life out of my  garden, which has full sun for most of day. (Toronto)
Since you still have full sun even with the hedge, here are some grasses that should tolerate drought or dry soils as created by the roots of the hedge (even though some may be listed for better soils).  For shorter ornamental grasses 2 to 5 ft tall, consider Big Bluestem (Andropogon gerardii), Fountain-grass cultivars (Pennisetum setaceum), and Little Bluestem (Schizachyrium scoparium).  For tall grasses over 5 ft tall, consider cultivars of Eulalia (Miscanthus),. Switchgrass (Panicum), Feather Reed Grass (Calamagrostis), or Moor Grass (Molinia).  For the latter, the clump of leaves is a couple feet high, but flower spikes taller.

*What are the most common problems I should be aware of with soils? (VT)
If a soil has a problem in our area, it is often too low pH or too acid soil.  This can be corrected by adding lime, according to the soil test.  A soil pH that is between 6 and 7, 7 being neutral, is often best.  A soil pH that is too low or too high makes nutrients unavailable to the plant. Soil test sampling bags are available from state agriculture testing labs, often at state universities, or from garden centers.  If purchasing inexpensive soil testing kits you can do at home, make sure they are new, as old chemicals in such kits can give wrong results.

*I'm just getting into gardening.  What are ten of the most important items I should have? (VT)
Of course what is useful in one garden may not be in another.  The most useful items to me are a good pair of gloves, such as goatskin, that last through the season; a good weeding tool, both for hand use and one for standing; a collapsible rake;  a good mulching mower for returning grass clipping back to the lawn to recycle nutrients and organic matter; a good source of compost; a good garden cart; a good wheelbarrow; hat; suncreen; and insect repellent.

*How can I grow root-invasive perennials such as mint in the garden? (VT)
You can of course keep up with the new shoots as they emerge, weeding often.  Easier perhaps is to plant the pot, and sink the pot in the ground.  Just make sure the roots don't escape through pot holes (remove the pot monthly to check for this), or over the top (keeping the lip or top of the pot above the soil surface will help).  You'll also need to divide the plant and repot at least yearly, as it wants to spread and when confined may weaken or die out.  Other root-invasive perennials such as some of the loosestrifes (Lysimachia) dwarf (punctata) bellflowers can be treated similarly.

*How do I keep the neighbors' cats out of my flower beds.  We've tried all kinds of repellents such as pepper, enzyme from the vet, and moth balls (which everyone suggested first).   When I put out moth balls the next morning I had three cats laying all over them.  They will go back into their own yard before we have time to get the water hose out. (TX)
Is there something such as catnip in the bed that they just can't resist? Perhaps an organic fertilizer? Try to figure out what is attracting them so much and remove it.  You might try other repellents such as predator urines.  Many with pet problems have success using a hose attached to a motion sensor you can buy just for this purpose.  When the animal gets near the hose turns on them.  You might also try talking to your neighbors, or getting a dog.

*Are there tall grasses or flowers, even vines, I could plant on top of a septic leach field to hide a fence also on top of the field?  (NY)
Best would not be to plant tall (3-6ft) grasses (most are not from seed but rather divisions) as they may have deep roots that would interfere with the leach lines.  Often recommended is just lawn, or annual flowers.  If planting perennials, used those such as yarrow with more shallow roots.  To hide the fence consider annual vines such as scarlet runner bean or Black-eyed Susan vine.  Many perennial vines such as honeysuckle or hops may have deep roots that would interfere with the leach lines as well.

* This time of year (early March) leaves on our hellebores are ugly and detract from the emerging flowers.  Can we cut them off without causing harm to the plant?  (NC)
Yes, late fall through late winter have all been recommended as times to cut back the old leaves of hellebores which usually flatten out in winter and turn brown.  Plants usually put on new growth and leaves with warmer spring temperatures, growth that should be hardened to possible late frosts.

*I am looking for a tall fast growing grass to provide coverage next to a busy road that will stand up in the winter too.  Do you have any suggestions?  (MN)
Several of taller (usually 3-5 feet) ornamental grasses that supposedly resist road salt, the main issue along northern roads, and that are hardy are the feather reed grass (Calamagrostis acutiflora), switch grass (Panicum virgatum), and cord grass (Spartinia).  As with most grasses, heavy winter snow or ice can knock them down.

*We've tried starting gladiolus indoors from small bulblets we collected last year.  It has been 6 weeks with no signs of growth.  Any tips or clues? (WI)
The gladiolus "bulb" is actually a modified base of a stem called a corm, the bigger offsets each fall you dig the new corms, the smaller ones the cormels.  These may take two or three seasons to produce flowering corms.  Each year when planted they don't get bigger, but produce a corm that is larger.  The first year, and maybe the second, just expect grassy foliage.  Cormels are slow to germinate.  Check and make sure they are still firm, not rotted, or shrivelled.  Soaking dry cormels in cool running water for one or two days, then holding in moist peatmoss, may help hasten growth.

*You mention to make late-blooming perennials such as asters and Helen's flower shorter and more bushy to cut back by a third.  Is this a third overall from the top down, or thin out a third of the shoots?  (Vermont)
Cut back in early summer, mid to late June in Vermont for instance, by one third overall.  The plants will then branch from below this point, meaning a denser habit and not as tall so hopefully not needing staking.  You can cut back even later for even later fall blooms.  I once cut back a garden phlox in late July, with blossoms still  in late October even after freezing and frosts!

*I have hostas with twisted, stunted, and puckered leaves.  Is this normal, or a disease?  (Vermont)
It depends, some varieties show this normally, but there is a relatively newly discovered virus that could be the cause, called Hosta Virus X or HVX (a Potexvirus).  Some varieties over the years such as Eternal Father, Lunacy, and Leopard Frog actually have their traits due to less virulent viruses.  This virus though causes traits as you note, and is highly contagious through contact of infected sap from one plant with another.  This is commonly spread by hands or tools such as through pruning, so make sure to wash in between with antiseptic soap.  As with other viruses, there are no cures, so infected plants should be discarded.   Also like many viruses, plants may carry this one yet not show symptoms, which makes diagnosis sometimes very difficult.  The cultivar Breakdance has been reported 100% infected, while commonly infected cultivars include Gold Standard, Striptease, and Sum and Substance.  Before buying these, or in fact any hostas, get familiar with what they should look like, and don't buy them if they look otherwise.  It is easiest to see symptoms on gold and gold-centered plants, which in addtions to those you note, may include random green mottling, and mottling along the veins.  Since this virus must be transmitted in sap and living plants, you can safely plant where an infected plant was removed as long as there are no living roots from the old plant.  Considered resistant are the cultivars Blue Angle, Color Glory, and Frances Williams.  Considered immune are Bressingham Blue, Frosted Jade, Love Pat, Great Expectations, Sagae, and sieboldiana Elegans.

*Are Japanese beetle traps a good control for these pests?  I've heard both yes and no. (Vermont)
These traps attract beetles using a powerful odor.  For this reason some recommend placing them upwind from your gardens, so any beetles you have will be attracted to it away from your desirable plants.  Keep in mind that at best only perhaps 75% of beetles will be caught, hence one reason some don't recommend them as  you may end up with more beetles and feeding.  Beetles will feed along their way to the trap, so make sure you keep traps as far from your gardens as possible.  They are most effective in settled areas when a whole community uses them.  Keep them emptied often, and change them at least yearly if not more often, as the lures inside go stale.  The scent of dead beetles may repel living ones, so some gardeners pulverize the collected beetles and spray on their plants as a control!  Least toxic biological controls include neem oil, pyrethrin, rotenone, and beneficial nematodes.  Make sure if using to apply at correct times, read and follow all label directions and precautions.

*I have lily leaf beetles.  Is there anything I can do to the soil to control these beetles?  (Vermont)
Unfortunately there isn't much you can do to the soil around plants, as these beetles may overwinter away from host plants in woods or such.  Best is to start watching plants almost daily as they emerge in spring for reappearance of the red beetles.  Handpick, or use neem regularly which will repel adults and kill young larvae.  Hopefully research at the Univ. of Rhode Island with biological predators (from Europe, where they already effectively control this pest), will yield useful controls in the near future.

*I have lots of yellowjackets around our yard which makes me uneasy gardening.  What can I do?  (Illinois)
Bees are actually good in the garden, especially for pollination, and are seldom a bother unless really provoked.   Often confused with bees are yellowjackets, which pose a much more serious threat. Without barbs on their stingers as bees have, yellowjackets can repeatedly sting their victims.  They are most active in late summer when their colonies reach their peak, and they need higher levels of protein-rich or sugary foods. Get rid of their most important human source of food, garbage, and you'll go far towards getting rid of them.  Keep garbage covered, and dispose of it frequently. You can also use food to trap them.  Make traps of one-liter size soft drink bottles.  Bait these with left over soda, cat food, ham, tuna, or over ripe fruit.  Then place at the farthest corners of your property.

While working in the garden you can protect yourself from stings with a few simple measures.  Avoid wearing brightly colored and patterned clothes.  Avoid wearing perfumes and other scents such as from deodorants, scented hairspray, or from suntan lotion. Maintaining your composure around yellowjackets, or if they land on you, also can help prevent stings.  Squashing a yellowjacket also releases a chemical alarm that signals others to the area to attack!

Although yellowjackets make paper nests similar to other wasps, they usually build these nests underground.  If you notice them flying about your garden, use caution when weeding!  Watch for underground nest openings they may be entering and leaving.  Using the proper precautions, you can spray these openings in evening and again in morning.  Use a wasp and hornet spray that reaches 20 feet, and leave immediately upon spraying.

*Is it better to water daily when plants are in the sun or once a week? (Connecticut)
After just planting, you may need to water perennials more often, especially if it is dry.  Otherwise, and after the first month or two, a good soaking once a week is better than more frequent light waterings.  This helps promote deeper rooting, rather than surface roots that dry out quickly.  Mulching will help decrease the amount of watering, as will lots of compost or organic matter in the soil.  Annual flower are the opposite--water less when first planted or they may stay too wet.  Once established, they may dry out quickly and need watering every day or two if no rain, or light rain.  This is especially true if in containers, more so if small containers or clay ones.

*What perennials don't moles eat? (Virginia)
Actually moles don't eat perennials, they eat insects and earthworms.  It is the voles or meadow mice that are eating garden perennials, in addition to grass seeds and stems.  Moles have paddle-shaped front feet for digging.  Voles resemble furry mice with short tails.  There are some commercial repellent products, and even more home remedies, to control these.  Many of these seem more annoying to humans than moles and voles, and are often of little effect.  Poison baits are not recommended as they can be quite toxic to non-target organisms (humans, pets), and work their way into the wildlife food chain.  The best control seems to be traps.  I use a mouse snap trap, baited with peanut butter, and placed at the opening of an active tunnel.  I then cover the opening and trap with a clay pot, which is attractive, keeps other critters out of the trap, and makes the critter think the trap is in the tunnel.  Traps are most effective in spring and fall when these are most active.

*I'd like to know what perennial summer flowers rabbits/squirrels won't eat? (Pennsylvania)
I haven't seen a list of flowers rabbits wont eat, but you might try interplanting them with plants they don't like the odor.  These include garlic, onions, Mexican marigold, and dusty miller.  If they're not too hungry, you might also try sprinkling blood meal, human or dog hair, or ground hot peppers around plants.  Sometimes soda bottles, buried with the tops sticking out (they whistle in the wind) are effective.  Commercial repellent sprays are often effective, but I've learned you must cover ALL parts of the plant (just spray the leaves and they'll eat the stems!).  You can make your own spray with a few teaspoons of cayenne pepper, a few drops of dish soap, in a quart of water.  Such taste and odor repellents may also be effective on squirrels.  If all these fail for rabbits, fencing is the most effective.  Make sure the poultry wire mesh or similar is about 18 inches above ground, and at least 6 inches below ground.

*We have lots of woodashes.  Can these be put on the garden without harming it?  (Massachusetts)
Woodashes act much like lime, raising the pH or alkalinity of the soil.  Unlike lime, though, they act much quicker so if you add too much the soil pH can get too high for good plant growth.  Soil pH for most plants should be in the 6.0 to 7.0 range.  If it is there, you probably shouldn't add much or any woodash.  If near 6.0 or lower, a safe recommendation is 20 pounds per thousand square feet yearly, translating to about a 5-gallon pail.  Since wood ash also adds potassium, and many soils have sufficient phosphorus, you may only need to then add additional nitrogen.  A soil test can tell just what you'll need.  Check with your local Extension office, Master Gardener program, or state university for such kits.

*When and how do you divide peonies?  (Michigan)
Peonies unlike most perennials really prefer dividing in the late summer even through late fall.  Unless they are growing too large, too crowded, have fewer blooms, or you want plants to move or share, they really can last many years without dividing.  Cut off stems, dig the clump, and divide it with your hands or sharp pruners into sections having at least 3 "eyes" or buds.  Then make sure and replant so these buds are at the soil surface.  Plant too deep, and peonies will grow but not bloom.  I always like to add a little phosphorus in the hole before planting, such as from superphosphate or rock phospate (very little), to aid root growth.  Water well, and if you mulch for winter, be sure and remove the mulch in the spring.

*I have retrieved some Stella d'Oro daylily seeds from my son's very successful plants.  Now what do I do to propagate them? (Illinois)
Since daylilies cross so readily (as do many other perennials), there is no guarantee seeds you collect and sow will be anything similar to the mother plant, in most cases probably not.  This can be good if you want to see what you come up with, as breeders do in a controlled fashion.  If you want to assure the same plant, you'll need to propagate it such as by division.  Sow seeds fresh, and even then they may take several months to germinate.  Or you can hold in moist peat and keep around 40F for 6 weeks prior to sowing.

*I have a Final Touch daylily which has never bloomed.  I have had it for 3-4 years. (Oklahoma)
Usually a daylily should bloom by the third year, even if from small division.  Possible causes for lack of bloom might be too little light (they really need full sun, or mostly full sun), too wet or too dry stressing the plant, or perhaps too much fertility (if the plant looks vigorous and green but wont bloom).  If none of these fit, try different culture, or try stressing the plant a bit (less water, less fertility), and sometimes this may trigger bloom.  Even moving to a different location may help sometimes.

*I have several coreopsis plants.  Should I cut off the dead blossoms, and if so, where do I make the cuts? (New York)
You dont really need to cut off the past flowers of coreopsis, other than for aesthetics.  If so, and there are usually so many flowers, it is often easiest to just use grass shears to cut the plants below the flowers, leaving most the leaves on the stems.

*I've been picking tons of asiatic garden beetles off my flowers.  Is there anything I can do? (Rhode Island)
These beetles are chestnut brown and look similar to a Japanese beetle, and have a similar life cycle, but don't skeletonize leaves rather strip them, often just leaving a midvein.  If this is what you have, you likely have this beetle.  They like moisture, so this year with all our rain we've seen many, even here in Vermont.  They seem to be mainly in the northeastern U.S., are attracted to light, and feed at night dropping to the ground during the day.  The grubs feed on turf, the adults feed on many flowers and vegetables during July and August.  Control grubs in July through mid-September with approved pesticides, making sure to read and follow label directions.  Keep in mind some products may also kill beneficial insects.  Products for adult beetles may also be used with the same precautions.  Few if any specific biological products are available.  Of course handpicking may also work if few in number.

*Are the blue lupines seen in June in fields all over northern New Hampshire and Maine the native lupine perennis or are they escaped non-native garden plants?  Any good suggestions for blue native flowers we can plant? (New Hampshire)
The blue lupines are likely the native species, compared to hybrids which are generally in other colors.  Some other native blue options for the Northeast might be the blue lobelia (Lobelia siphilitica), Blue Stars (Amsonia), Blue false indigo (Baptisia), New England Aster, and Virginia Bluebells (Mertensia).

*I will be moving from in September. I have 3 favorite perennials including hosta and peony I would like to take with me. What is the best way to transport them. (Ohio)
Although spring is ideally the best time to move perennials, as growth is starting (except peonies which are best moved in the fall), fall is the next best time.  The earlier in fall is best, to allow plants enough time to reestablish.  Otherwise you may be better off overwintering in pots, in a cold but nonfreezing space.  If you can't get the plants back in the ground within a couple days, it is often best to hold in pots of soil, even if temporarily before planting.  Keep moist but not wet.  Cut back top growth by half to 2/3 to balance the loss of roots.  In the case of hostas and peonies, this would mean cutting off all top growth.

*What kinds of plants can be planted along a non-spring-fed pond to help keep it clean? This is a large pond , over an acre, and I understand that cattails and other plants will help filter the pond water. (Vermont)
You're correct, cattails are probably the best known water plant, along with reeds and rushes, whose dense root systems absorb excess nutrients.  Pickerel Rush helps scavenge decaying organic matter, reducing food sources for algae.  Aquatic mint is quite aggressive, so is excellent to keep algae away.  Taro is fast growing, absorbing excess nitrogen and storing it in edible tubers.  Others that are effective at keeping ponds clean are Duck weed, Fairy moss, and Water hyacinth.  Keep in mind that many such aquatic plants are considered invasive in many areas, and may even be banned in some states.   If using such plants, make sure your pond is contained and there is no way such plants can reach waterways.  Many of these may also be hardy only in warm climates, so have to be treated as annuals in the north.

*As a bride to be I am drying pink rose petals to use in my invitations.  I'm pressing them between sheets of paper in a heavy book, but find they are losing their colour.  Can you please offer me any advice as to how I can insure my next batch of rose petals keep their lovely strong bright pink colour? (London, UK)
Commercial firms use expensive freeze drying to preserve roses and other flowers so they look fresh.  There are several methods to dry flowers such as roses at home.  Keeping them out of the light as you did is a first step to preserving their color.  The method you used of pressing and drying between sheets of paper, while keeping light out, often may not be best to preserve the color though.  A more recommended method is to gently, but completely, immerse the flowers in a container of the drying material silica gel, available at many craft stores.  Or you may use various combinations of sand and borax and cornmeal, such as 1 cup sand, 2 cups borax or 1 cup borax, 1 cup cornmeal.  Just watch for insects that might be attracted to the cornmeal.  You may also try a layer of petals on a sheet in a warm oven.  You may also try the microwave, in which case you should also put a cup of water in with a few flowers at a time.  Put flowers between paper towels, use low power, and only a minute or two at a time.  Flowers may lose color and become brittle, however, in a microwave.  Dehydrators, as used for vegetable slices, also are used by some.  Some varieties, in spite of all this, just don't dry well and keep their color.  I hope yours isn't one of these.  good luck!

* Since my black-eyed susans began to grow this spring, their tops look as if someone came along with a sharp instrument and cut them off.  They grow again, and the same thing occurs.  What is causing this problem? (New York)
Do you have deer nearby?  They, or possibly other mammal such as groundhogs, even rabbits (if not too high) can cause such injury.  Late summer blooming perennials such as these may not be affected, IF no more injury, they just may bloom later.  You may want to try smell repellents such as bars of soap hung nearby if deer, or taste repellents such as pepper sprays on the plants. If they are real hungry though, only fencing out will help.  If plants don't bloom this year, they should come back fine again next year.

*I recently bought a Concord Grapespiderwort.  You mention in your article to cut back after bloom when the foliage gets ratty.  Mine has reached the ratty stage and my question is how far back should I cut it? (Vermont)
You'll only need to cut back spiderwort (Tradescantia) if the foliage becomes unsightly or infected with rust after bloom.  Otherwise, only deadhead back to lateral buds which will then bloom.  If needing to be cut back, do so by 2/3 or to the ground, as new growth will emerge from the base. It will be shorter, and bloom more sparsely.  If stressed by heat or drought or such, it may not rebloom.  Keeping the soil moist helps promote rebloom.

*Can I plant hostas under a maple tree? (Illinois)
Yes, in fact these are one of the best just choices.  Just make sure and keep plants well-watered the first few months or year until they are established.  Other choices might be vinca vine (if not invasive in your area) underneath, and daffodils between. Foamflower, barren strawberry (Waldsteinia), and dead nettle (Lamium) are some other choices.

*I have a problem with earwigs eating my flowers, especially hollyhocks, zinnias, and roses in bud. How can I control them safely, as I also have pets.  (Colorado)
Earwigs are among our least favorite insects, but they do serve a positive function of eating aphids in the garden. If
you have a heavy infestation of aphids, this could be helping to attract the earwigs. Aphids can be treated with
insecticidal soap, devoured by lady bugs, or knocked down with a strong spray of water from the garden hose. I would
not suggest washing them off in your case however, since earwigs like moisture.

Earwigs tend to build up in an area with decaying organic matter combined with constant moisture. Watering regularly at night, a wet spell of weather, overly thick organic mulch, and decaying plant material can all make an area attractive to them. If you can make the area less attractive to the earwigs, they should decline in number.  Fluff the mulch with a rake to help it dry out.  Avoid daily sprinkling or light watering in dry weather, instead, water deeply less often. Next, you can try catching and trapping them. Although time consuming, hand picking at night by flashlight is best.  Chemical controls are also possible.  Check with your local garden center or Extension Service for locally approved ones.  (answered by Nancy V.)

*Can I use horse manure mixed with wood shavings in the garden?  (Vermont)
Using this fresh may rob the soil of nitrogen, as the microorganisms breaking down the wood uses it up.  One solution would be to add 30-50% more nitrogen to the garden.  Or you can first compost the manure and wood mixture, adding more nitrogen there as well to aid proper break down.    Beware any fresh manure products for weed seeds.  Horse manure is usually pretty safe, if they have fed on weed-free straw or grass.  Any manure from animals feeding on hay with weed seeds will add these seeds to your garden, unless it has been composted properly and at high temperatures.

*Books say to cut lavender back in the spring, but we live in a cold zone in Vermont and never do.  Should we?  (Vermont)
First, to survive in your USDA zone 3 climate (they are rated zone 5 at least), you must have good snow cover!  If they survive fine, then no need to cut back.  In marginal climates, they often get straggly by spring, so cutting back helps stimulate new growth and make more uniform.  Cutting back in warmer climates does similar, and helps shape and keep at a certain size.

*If I bring primrose in to give as Christmas presents, what do I tell people about their care? (Toronto)
Primrose, especially the English ones (vulgaris species and hybrids) do make nice holiday presents as you suggest, potted in a good houseplant medium such as soilless mix. Just advise to keep them watered (don't overwater) and fertilized lightly after bloom. Yellowing leaves may indicate too low light, too cold, too hot, too wet, or hungry. Keep in a fair amount of sun indoors, in as cool as possible, even unheated areas if they remain above 40degrees F or so.  Then plant outside in spring after heavy frosts are past.

*Can you suggest the best perennials for a seaside garden in northern California, about 1 mile from the ocean on a high peak.  There's nothing between my yard and the Pacific Ocean.  It is quite windy and often damp throughout the summer due to heavy fog. (California)
You might consider some of the many aloes and agaves and fuchsias.  Other flowering perennials might include thrift (Armeria), Santa Barbara Daisy (Erigeron), Sea Holly (Eryngium), Sunrose (Helianthemum), Daylily, Coralbells, Candytuft (Iberis), Torch Lily (Kniphofia), and Perennial Geranium (Pelargonium).  Some for foliage might include Blue Fescue, Hosta, and New Zealand Flax (Phormium).

*Do  you have any tips for creating a winter garden or caring for a winter garden in Southern Cal? (California)
Gardening and plants really depends on location in Southern California, as there are many microclimates created by mountains, canyons, deserts, and ocean.  Areas near the coast remain mild and so adaptable to a wide range of most plants that don't require cold to bloom.  The exception would be some canyons, such as near Laguna Beach and San Clemente that can funnel cold winter winds, dropping temperatures near or below freezing.  Hardier plants, and some winter protection might be needed in these areas. Other inland canyons might funnel the hot and drying fall and winter Santa Ana winds.  Protect plants in these areas with windbreaks, row covers, and sprinklers.  Some areas are transitional, with influences both from the ocean and inland, sometimes in the same day.  Temperatures can vary widely in these areas, often providing enough heat for oranges yet enough cold for many temperate perennials and shrubs such as some lilacs with less chilling periods to bloom.

Plants often found in Southern Calif. include many from the Mediterranean, Australia, South Africa and similar climates.  Such a garden might include succulents such as Aloes and Agaves, with Protea family species such as Banksias, Grevilleas, Proteas, Leucospermums, and Leucodendrons.  Other winter blooming perennials one might find say around Los Angeles might include Clivia, Iceland Poppy, Ice Plant, Mesembryanthemums, some Narcissus (those with minimal cooling requirement), and many South African bulbs.

*It's fall and I am moving and want to take my perennials with me to my new house, how do I do this without harming them? Do I plant them outside or in pots? (Indiana)
When moving perennials in the fall, get as many roots as possible, cut the tops back to balance loss of roots, and keep roots moist.  Best to move as soon in  fall as possible.  If moving a short distance, you can go on and plant.  If moving over a longer distance or time, you can pot temporarily (this works in summer too if you can't replant right away, or don't know when you can replant).  Best to replant in the fall, and mulch well to help keep ground temperatures warmer and roots growing longer.  You can hold in pots if a cool, non-freezing area with light-- just keep moist.

*How do I control the Japanese beetles that devoured my roses this past season?  (answer provided by Marilyn W.)
Beetles appear in late-May. They often prefer to feed together in masses on flowers and foliage of plants leaving large round or irregularly shaped holes. They feed in the daytime and prefer bright sunlight, beginning with the top of the plant and working downward. Odor seems to be a very important factor in their food selection. Populations usually peak in June and taper off through July.

Early in the morning, before the beetles become active, pick off or knock off by hand into a can of water covered by a film of oil or kerosene.  Be aware that many pesticide chemicals, while effective, may be toxic to beneficial insects, such as bees. Read all the instructions carefully, and follow all the precautions when using chemical treatments. Japanese beetle traps with pheromone lures to mass-trap them can actually make the problem worse, by attracting more than they kill, and so often are not recommended. Pesticides commonly used for lawn grub control  will also control Japanese beetle grubs as will milky spore disease, although results are often erratic. Try interplanting with species that may actively repel the adults-- white mums, rue, tansy, larkspur, garlic, and citronella. Covering with floating row covers can protect prized roses and ripening fruit.  Cut your roses as soon as them begin to open and take them inside to enjoy.

*My daffodils and amaryllis are softy and mushy, with grubs eating inside.  I understand this is from the narcissus bulb fly.  What do I do for control?
As you probably already have seen, the grub or larvae of the bulb fly destroys the insides of the bulb, and is difficult to control having few natural enemies.  It will affect not only daffodils but many other bulbs.  It comes from an egg, laid by a female fly in early summer that resembles a bumblee bee.  Unlike bees though, these flies have a rapid flight, tend to hover, and are looking for dying bulb foliage instead of flowers.  After mating the female lays eggs at the base of dying bulb foliage, the egg hatches and the larva tunnels down into the bulb scales and then feeds its way into the bulb center destroying it. It will pupate in the spring, giving rising to yet more flies to start again.

An effective but time-consuming control is to watch for the bees and catch them with butterfly or insect nets, each one caught preventing 100 or so larvae. Or you can "hide" the old foliage from the egg-laying flies by dense groundcovers such as ajuga, pachysandra, or vinca.  Instead, or while these are establishing, you may cover bulbs with lightweight ground cloth until midJuly.  Planting bulbs in grassy areas, or among perennials which will hide dying foliage should also deter the flies.  Cut off dead foliage immediately as it dies back in early summer, and cultivate around bulbs to hide the remaining bulb tops from the flies.  Apply diatomaceous earth around bulbs every 10 days in late May and June to deter grubs.  Pyrethrin or rotenone dusts have also been recommend where available and legal. An insecticide drench may also be applied in early May--check local stores for current products.  If a few bulbs, they may be dug up and infected ones (soft, mushy) discarded making sure to kill the larvae.  More tricky is a hot water bath, 110degree F for 30 minutes, but avoid much hotter as it may damage the bulb.

*What product or process can I use to keep squirrels from digging up our bulbs after we plant them. (Wash.)
Often squirrels, skunks and other small animals are going for what you plant with the bulbs if they smell bone meal.  So use a non-fragrant source of phosphorus such as bulb food, rock phosphate, or superphosphate.  If already doing this, try daffodils which most animals tend to leave alone compared to tulips which most like.  If planting singly, sprinkle some crushed rocks or shells (you can buy them just for bulbs) in the hole after you place in the bulb.  This deters digging noses and paws. If all else fails, over the bed with wire mesh such as chicken wire, or make a cage buried in the ground to plant into.  If local laws permit, you can also try trapping squirrels and chipmunks with the cage-type traps and relocating them.

* I have a large zone under pine trees.  I would love to have a shade garden there but have heard that it is difficult to get anything but fern to grow in the shadow of pines.  Do you have any suggestions? (Michigan)
This situation involved not just dry shade, but acidic soils as well from the pine needles.  Some plants I and others have found success with under coniferous evergreens such as pines include epimediums, wood poppies, violets, columbines, european ginger, snake root, sweet woodruff, lamium, bishops weed (quite root invasive), yellow cordalis, bearberry, bunchberry, blueberry, wintergreen, woodland anemone, coralbells, bleeding heart (eximia species and cultivars) and hosta.

* I just planted black eyed susies about two months ago.  They were doing great, alot of blooms and then in a matter of two days, the leaves all turned brown and they are dying.  Nothing else I have planted there has done this.  What could be the problem.  (New York)
Something this quick sounds like a bacterial blight, which may have come with the plants, or invaded due to some insect damage or other stress.  Most fungal diseases work slower.  If blight, you should see blackened areas when you scrape the top layer off of the stem surface.  Something disturbing the roots such as moles or chipmunks would result in slower wilting first and eventual browning of leaves.  If a blight, digging and discarding (not in compost) is the only solution unfortunately.  I might also wait to replant something in that spot until next year, and preferably not the same plant for a couple years.

*I have about 1/4 acre of lawn invaded by the perennial bugleweed.  I do not have this in my garden, but think it came in with bark mulch.  What can I do to remove it permanently? (Vermont)
Short of scrapping the entire surface of the area, or removing it such as with a sod cutter, putting new soil and grass seed down, you might try a herbicide if not philosophically adverse to such.  The "organic" ones which are basically heavy salts and just burn foliage, wont really get the roots.  A broadleaf one (some of these may  persist in the soil) will get any broadleaf plants and other weeds in your grass.  A systemic one such as Roundup kills anything green, which if just bugleweed there and no grass, that may not be a problem.  A small area can be covered with black plastic for a few months or year, and hopefully the heat and lack of light will kill the plants.  If you have this or similar plants in perennial gardens, make sure you keep them in the beds with proper edging!

*What are some organic methods of controlling insects and diseases on herbaceous garden plants? (New York state)
There are many controls that can be considered organic.  One is to plant cultivars that are resistant to certain diseases, or that repel certain insects.  You can use trap crops to lure the insects away from more valuable crops.  Crop rotation helps to minimize insects and diseases, by not giving them time to get too well established.  You can also remove insects by hand, or using certain devices to catch them.  There are also plant derived organic pesticides that can be used to control insects.  You should never reuse soil where diseased plants have grown, or put diseased plants into your compost.  (answer by C. Lynch as part of PSS course)

*Could you tell me whether deer eat daisies. I love daisys and recently moved near woods with a deer population. (New York)
Daisies (Shasta) are usually resistant to deer feeding, but if too many deer or hungry enough, they will eat most plants.  You can find more "resistant" perennials in my online leaflet (http://www.uvm.edu/~pass/perry/oh64.html).

*I have a plant which was sold as "ghost plant."   I have grown it in my garden and it has white plumes something like astilbe but it is about 5 feet tall.  Can you tell me what I have and whether or not it will perform in dense or filtered shade? (Illinois)
That's the problem with common names, and why you should encourage your nurseries to also list the scientific names!  There are several plants called ghost plant, but most are desert or tropical or such.  What you probably have is Artemisia lactiflora, often known more commonly as mugwort.  There is a photo of a popular cultivar Guizho at the Blooms of Bressingham site (http://www.bobna.com/products/artemisia_lactiflora.htm).  If this species is it, it should be hardy in your hardiness zone 5, but isn't in our zone 4.  It really needs full sun to grow best, and may be poor in shade.  It needs well-drained yet moist soil as well.

*I'd like a list of new perennials for this year, ones that need to be better known.  (Pennsylvania) 5/03
This is one of the most fun to me, yet hardest items to keep up with, as there are just so many-- many more than with annual flowers it seems.  Many growers have their own introductions, and there are always new ones coming into the U.S. from abroad.  First, visit your local full line garden center or specialty perennial nursery.  Also visit such online.  One national program, with retailers in most states, that introduces new plants from the UK is the Blooms of Bressingham program. You can also check out my monthly perennials from the homepage on this site to see new selections including perennial plants of the year, or existing but good and underutilized ones.  Past selections can be found under the A-Z listing of plants, also from the homepage.

*I'd like to plant some heather, do they need full sun or will they take part shade? (New York)
Heather prefer full sun, but tolerate part shade, just don't bloom as well in part shade.  Other keys to their successful culture (USDA zones 4-7): don't overfertilize, plenty of water, acidic soil, very well drained soil, sandy soil is best.  Give some winter protection such as evergreen boughs, to prevent drying in spring prior to new growth.  If vigorous, cut back about half way in spring prior to new growth.

*I'd like to make some cuttings of perennials, how do I go about this?  (Vermont)
There are several types of cuttings described, and some common plants listed, in our leaflet on Rooting Cuttings.

*Could you recommend some perennials for part shade, under adrip line of a roof?  (New Hampshire)
Obviously you don't want tender stems that can get beaten down with heavy rains.  Some of the stronger, more upright ferns such as Royal and Cinnamon would be good for 3ft or so.  Perhaps bergenia, or some hostas for lower heights-- just make sure you get upright selections of the latter without the large tender leaves. For low groundcovers consider bearberry, vinca, or ajuga in cool climates, and additionally liriope and mondo grass in warm climates.

*What are some plants I can use to attract hummingbirds to my garden?  (Maine)
Some of the best perennials and biennials to attract hummingbirds include hollyhock, columbine, delphinium, foxglove, daylily, coral bells, hosta, blazing star, bee balm, and garden phlox. Some good annuals include flowering tobacco, scarlet runner bean, salvia, and even single petunia.  Whether annual or perennial, avoid the double flowers as they are difficult for hummingbirds and insects alike to pollinate.  Choose a selection to provide color through the season, a succession of flowering times. For more on how to choose flowers, and other important aspects for hummingbird habitats, see the leaflet on this topic. (http://pss.uvm.edu/ppp/pubs/oh76hum.htm)

*Is there such a thing as a perennial that will flower throughout the summer?  Shady and sunny areas. (Kentucky)
As you probably know most perennials bloom on average 2 or 3 weeks.  I know of none that bloom continually in shade, although a couple that may bloom for many weeks are the spotted deadnettle (Lamium) and tuberous begonia.  In sun, some perennials including many shrub roses (many hybrids such as tea roses bloom pretty much continually) may either rebloom later in the season (other examples are some perennial salvia and some perennial geraniums), or more often depending on plant and location.  Your best bet is to pick a selection of various cultivars of a plant to get a succession of blooms.  This is particularly true for such large genera as daylilies and geraniums, which for me provide blooms from June through September, and May through August respectively.

*I have some small perennials in pots in a hobby greenhouse.  How should I treat them so they will get cold and bloom next season? (Toronto)
It sounds like your perennials are protected in the greenhouse, at warmer temperatures?  I would decrease the temperature maybe 5-10C (10-20F) a week until it is about 5C (40F) or a little lower.  It doesnt sound like the plants are large enough, or established enough to take much freezing, hence keeping them about this.  That should give them some cold, which hopefully will help blooms.  Perennials all vary, some need cold, others dont, and some vary in the amount from 4 to 12 weeks.  It is the longer days in spring that gets them growing again, so the sooner in fall you can give them cool temperatures the better, so sufficient time if they need cold, before spring.  I would still keep them fairly cool even when they start growing, otherwise they might grow too fast, bloom, or get too leggy before you can put them out safely.

*How do I improve heavy clay soil?  (Delaware)
The best way is by adding organic matter (not sand), and lots of it!  This could be shredded leaves and grass clipping from your yard or local recycle/landfill center, compost, peat moss or similar.  This may need doing each year for several years.  Of course a quicker approach is to dig it out and replace the soil, but this may be more expensive.  More tips can be found at our garden leaflet on Gardening on Clay.

*My daylilies haveorange spots on the undersides of leaves and plants don't look good.  What should I do?  (various)
This is most likely a new disease, found now in at least 20 states and Costa Rica, a fungal rust called what else, daylily rust! (Puccinia hemerocallidis) This is an Asian species, imported and first seen on plants in Georgia in 2000.  It can merely cause the characteristic raised rust colored spots on leaf undersides to killing foliage. Some cultivars appear more susceptible than others, with Pardon Me one of the most susceptible.  Happy Returns, Stella D'Oro, and Joan Senior are popular moderately susceptible cultivars. Holy Spirit appears among a few others least susceptible.  Best control is by not introducing it, so if ordering daylilies or buying them in, some keep them isolated from others for up to 6 months or a season in the north to see if disease develops.  If present, cut off infected foliage.  Several fungicides for rust appear to control it, but should be rotated among different types every few sprays to prevent resistance. There are many websites on this disease, merely type daylily rust into your favorite search engine.

*This past year all my lily plants were devoured, buds, leaves even stems.  What caused this?  (New Hampshire)
If you see a fire engine red beetle with black head and legs, it is the lily leaf beetle (Lilioceris lilii).  Similar in size to the ladybug, it is slender instead of rounded.  This is a new pest from Europe, first reported in Cambridge, MA in 1992 and now ten years later throughout various parts of New England, especially the eastern half.  Not only the adult beetles do damage, but perhaps more is done by larval feeding, these ugly insects resembling slugs and carrying their excrement on their back to deter predators! They feed on members of the lily family including hosta and solomon's seal.  They don't apparently feed on the lily cultivar 'Black Beauty' though, nor daylilies which of course are not true lilies.  Control in spring by looking for and removing the lines of orange eggs on undersides of lily leaves.  Adults can be handpicked if not many.  Otherwise pesticides that kill beetles can be used, ones contained the plant extract Neem being least toxic to other organisms.  Although easy to control, new ones continually fly in, so spray weekly if needed.

*Does the last time I can plant perennials depend on how hardy they are?  (Vermont)
The last date perennials can be planted in the fall depends not so much on how hardy but rather on size of plant and soil type, and of course location.  Young, small, poorly rooted plants may not have sufficient vigor and root and crown mass to take low temperatures, but in more mild areas they may establish fine.  In cold areas experiencing frost heaving especially in the Spring, plants should be well-rooted so they dont heave out of the ground as readily.  This may be more in clay than sandy soils.  A couple points to keep in mind on rooting: perennials may need about 6 weeks (depending on soil temperatures of course) to establish some roots.  And roots generally grow about about 40degrees F.  In USDA zone 4, this may be until about first of November on average.  So for instance in USDA zone 4, mid September would be a good last date to plant.  Of course it could be later as noted above if large plants and good soil with little chance of frost heaving, perhaps even until the ground freezes.

*Local home improvement centers are now selling their perennials at half price (late fall)--is this a good bargin for zone 5? (Pennsylvania)
It depends.  You often get what you pay for with plants especially, so beware.  If you don't expect a lot from your plants, and are willing to put up with some losses, you may not be disappointed with bargains.  Many perennials are fairly tough, so it depends on what the plants are in part.  Also for a fairly cold zone compared to many in the country, just make sure the plants are hardy and truly perennial in your zone.  Look for information on the tags, or ask the sales staff.  Often with big chains, the buying is done elsewhere and the same plants shipped to all stores, so some may not be hardy.  And of course look for good growth, vigor, and lack of pests or disease problems.  Some big chains provide minimal if any maintenance of their plants, including watering.  Effects of such stresses may not be apparent now (unless plants are wilted of course), but may show up the following year with poor growth or even no survival.  So if you do get such plants, and they don't perform well, don't necessarily blame yourself for not knowing how to care for them!

*We would like to sow seeds from a hosta, and don't know how, or what the seeds are.  Please advise.  (Vermont)
Hosta seeds are ripe when the pods turn brown and begin to split.  If your season is too short for this, bring pods indoors and place stems in a floral preservative as you would for cut flowers, changing it periodically.  Place brown pods in paper bags to allow to split and discharge seeds, or if not, use tweezers or similar to remove seeds from the pods, blowing off any husks.  Seeds often germinate easily if sown fresh, otherwise store as you would other seeds cool (40F) and dry.  If not sown fresh, to germinate you may need to then sow in a moist medium, and keep cool (40F) for about 3 months.  Keep in mind seedlings are often quite variable from the parent(s).   The seedlings are often quite variable due to crossing with other nearby hostas.  Even if all parents are the same, or only one plant, there still is sometimes variability.  It often takes 2 years to get plants to show their true traits, in order to cull out ones not like the parent plant, and often 3 years to bloom from seed.

*I have purple siberian iris, with what appear to be seedpods and layers of seeds inside.  Is this correct, and will this take away from next year's blooms? (New York)
It does sound like the seeds, and these plants are generally pretty tough, so it shouldnt take away from next year.  If you have others nearby, they may cross and come up with other seedlings.  Otherwise, left on their own, they may self seed themselves, sometimes quite prolifically.

*I have 'Jacob Cline' bee balm and I would like to propagate them. What is the best way? (Pennsylvania)
As with most monardas or bee balms, root cuttings most times of the year are successful, or divisions as plants emerge in spring, or cuttings of new growth.  Easiest are root cuttings, with pieces of root laid in a moist medium such as potting soil, or half vermiculite and perlite.  Don't keep too wet.  Also easy is dividing off pieces of the main plant in spring, with several shoots per division.

*I can't seen to grow Black Eyed Susan in my yard - as soon as new sprouts come up they are eaten.  Any advice? (Connecticut)
It sounds like you might have rabbits? or groundhogs?  Usually deer eat off plants higher.  Have you noticed any?  Check out my leaflet on animals pests (http://pss.uvm.edu/ppp/pubs/oh52anml.htm) for more ideas on these, and other possible predators.

*Will bulbs grow up through a layer of mulch, or do I have to open up space for them?  (Vermont)
Yes, if an organic mulch and not a solid plastic covering material.  Use only a couple inches, which will in addition to helping conserve moisture and prevent some weeds, also help moderate soil temperatures in spring and fall.  In northern climates such as Vermont, the increased soil temperatures from only a couple inches of bark mulch may extend the rooting season for bulbs two or more weeks which is often quite beneficial.

*Canannuals and tender perennials be overwintered indoors?  (Vermont)
It depends on the annual, and indoor conditions, but many can if sufficient light and temperatures between 50 and 70 degrees F.  Or they may last through fall, giving some color indoors.  Just treat as a houseplant, fertilize according to label directions if growing and blooming, and watch for pests.  Coleus dianthus, and geraniums in particular are often overwintered indoors.  Tender perennials that we grow as annuals in the north, like many salvias, can also be held indoors if cool.  Too much heat, with too little light, for any of these may make them spindly with little or no bloom.

*Why do petals of my black-eyed susies won't open up? The flowers look so wierd. They have large dark center but the yellow flower petals are like pointed needles. (Toronto)
There could be several causes, but most likely either drought, or insect damage.  Often insects feeding in early flower stages, before buds even open, cause strange and distorted flowers.  Unfortunately the damage was done a while back if from insect feeding, so too late to control.  But the good news is the plants should be fine next year, just watch for insects when you start to see buds.  This applies to other flowers as well with such symptoms.
 

*Our Elijah Blue fescue has gone to seed. Do we need to remove the brown seed stems or leave them on? (Wyoming)
Leaving seed stems on grasses, including this one, is usually just an aesthetic consideration.  Often they can be quite attractive in fall and winter, especially on the taller grasses. On this grass, if you just want the bluish effect, you may want to remove them. The only time you would definately want to remove them is for seed invasive grasses such as some Miscanthus in warm climates (often they don't set seed in shorter and cooler seasons in the north).

*I found large grubs in bearded iris rhizomes when dividing them in late July.  What are they? (Vermont)
Iris borers.  Eggs are laid in the fall near the basal leaves and hatch in April. The larvae eat their way down, inside the leaf, until they reach the rhizomes. They then grow to 1-2 inches long with a soft, fat, pink body with a brown head.  Not only can the larvae eat rhizomes, but more damaging can be the bacterial soft rot which enters the wounds.  This often has a foul smelling odor. Larvae then enter the soil in late summer, pupate, fly around as moths in early fall and lay eggs for next year.
     Chemical controls prior to bloom may be effective, but best control is prevention.  Remove any diseased foliage in the fall.  Monitor in spring for small holes in the lower leaves where larvae enter and feed on their way to the rhizomes.  Then if signs of fairly quick dieback and poor vigor after bloom, check rhizomes for rot and cavities where the larvae feed before entering the soil.  Destroy affected rhizomes, and larvae (wire in their cavities works well), and sanitize with one part bleach to 9 parts water before replanting.  Check soil too for any larvae.

*I would like to know some good, environmentally friendly ways toclear out large grassy areas (acres)
to replace with wild flower seeds.  (Massachusetts)
The first thing to realize is that to have success with wildflowers over the long term, you'll need a good mix with many native perennial varieties.  And you need an excellent seedbed, and care, as if you were seeding a lawn. This can be difficult on large areas.  Of course some use weed whacking and mowing to lower grass levels, then kill it with roundup.  More ecological though is to lower grass levels as above, till thoroughly, then cover crop for several years prior in order to reduce weed populations.  If a smaller area, you may wish to cover it with black plastic for at least a  year after lowering grass levels, then remove and prepare the fine seedbed.  Even with all this, more competitive weed seeds from surrounding areas may blow in, and become established after a couple years, so reducing these populations if possible will also help.

*Are antidessicants effective? (New York)
Yes and no.  Antidessicants supposedly prevent dessication, or drying out, of foliage.  Many resemble latex type compounds, putting a film on leaves.  Over time this may wear off, and of course wouldnt be on new growth appearring after application.  Results for use over winter to prevent water loss from evergreen plants are mixed.  Often the spray needs to get under leaves where water is lost, as well as on top, and this may be difficult.  They generally though are effective sprayed on plants, especially evergreens, after transplanting to prevent excess water loss to help balance the loss of roots.

*What are some groundcover herbaceous perennials that would be salt tolerant?  (Vermont)
For salt tolerance of trees and shrubs, consult UVM OH leaflet 56,  http://ctr.uvm.edu/ctr/oh/oh56.htm
Some herbaceous perennial groundcover choices here would be bearberry, blue lyme grass, and wormwood.  Many can be massed for a groundcover effect, including low catmints and salvias, blue fescue grass, sea thrift, some Allwood dianthus (such as 'Helen'), some daylilies such as 'Stella de Oro', sea lavender, sedum 'Autumn Joy', and for warmer climates lilyturf.

*I need suggestions for Zone 5 groundcovers that will provide weed and erosion control on a slope in full sun. The soil has a mostly clay content and surrounds a pond. (upstate New York)
Slopes are a question I often get, and it seems a difficult situation to deal with.  There are several options, depending on your needs and budget.  You might terrace the slope, either with timbers into more formal levels, or place boulders either at random or more in organized bed fashion.  This will control erosion, and the terraces or levels can be treated as other flat areas either with grass or flowers or such.  Otherwise, Id suggest sowing a conservation grass mix.  This will have some weedy grasses usually, so is not best for formal lawns.  Into this you can plant perennials such as daylilies, many perennial geraniums, catmints, ajuga (more for shade), lady's mantle, bee balm, coneflowers, rudbeckia and ornamental grasses.  These will eventually grow and shade out grasses, and provide seasonal color.  You may also wish to add shrubs such as junipers or Russian cypress (Microbiota), which will eventually fill in too.  There are many junipers from low spreaders to taller spreaders.  Many of the shrub roses are good in mass too, especially the rugosa ones.  You might even use more root invasive plants, such as the Blue Lyme grass or Ribbon grass, as long as there is no chance they'll wash downstream in a waterway to spread to other areas.

*I have a problem with neighborhood cats using my tulip beds for litter boxes and destroying bulbs with digging.  How can I prevent this?  I do not know the pet owners. (Michigan)
I have this same problem with my cat in my beds before the bulbs emerge, or  in empty spots in beds, especially where I have a nice topdressing of compost.  I would think once plants emerge, this should deter them.  If not, there are some repellents you may find in garden stores to spray around.  Or perhaps just rough material like course gravel or shells, even egg shells, may work.  If bulbs arent up, you may cover beds with a fine metal mesh and remove it when bulbs appear.  This also helps prevent damage from mice, voles and such.  A courser mesh wire, like chicken wire, may be used before bulbs emerge, and also may allow them to come up between the wire and so be left on the bed.  Obviously a small fence around the area (but high enough so the cats wont jump over), may be a possibility as well in some situtations.

* I received a potted tulip as a gift. Is there a way to have the bulb bloom again, what is the procedure? (Mexico)
It is difficult to get bulbs forced in this way to bloom again.  It often may take a couple years, and tulips even planted out in the garden often are treated as annuals.  If you want to try, you can keep watered and growing until the foliage dies off, perhaps in summer.  You can leave in the pot, then in the fall give at least 12 weeks of cool, in moist not wet soil, at refrigerator temperature, about 40F.  Water with some liquid fertilizer then too. Then bring back into the warmth.  The bulb may grow, but not bloom well if at all.  Then repeat another year, perhaps it will bloom better the second year.

*I am trying to grow rugosa roses from seed. Didn't work last year.  Any suggestions?
Perhaps if these were seeds you collected yourself, they were not viable to begin with?  Or maybe they needed different storage (cool 40degrees F, dry is often best for seeds).  Or perhaps they needed different germination conditions.  Most rugosa roses spread more by roots, and root fairly easily by cuttings, so if seeds still don't work these might be options.  Keep in mind those from seeds may cross and yield flowers unlike the plants you got them from, if a particular color was of interest.  Try again, picking when just ripe, not soft, immediately removing the surrounding fleshy coat, then place in moist sand or peat at 40F for 6 months prior to sowing..

*With all this warm weather this fall, my perennials are starting to sprout and green up.  Should I mulch them, or leave alone? (New York)
I'd mulch for a couple reasons.  It will protect the new growth if tender, and it will help prevent ground temperatures from getting so warm on sunny days thus stimulating plant growth.  It can also prevent temperatures from fluctuating so much.  Even an inch or two of bark mulch can keep the soil 5 to 10 degrees warmer on a cold day than uncovered soil, or cooler than open soil on a hot day.  I'd also use some weed-free straw, or leaves that don't mat down (maple for instance) around the new growth.

*I had a very unpleasant encounter with a euphorbia this summer, and I'm still bearing scars from the awful blisters.  Please send me information about the toxicity of euphorbias, as no big deal is made in most books.  They just explain that it is a skin irritant. I had to go to a physician's office! (Vermont)
Yes, this is what most references will list for such skin irritants, the degree varying with the individual and the species of plant.  (I personally have no reaction from Euphorbias yet have heard of such a case as yours before.) If you learn from such experiences, or don't know, that you are susceptible to such irritants, treat all with caution.  Make a list of all the plants in your garden, checking them against references.  If you don't know a plant, treat it with caution until proven safe!  One place you may wish to start is my leaflet on Potentially Harmful Perennials.

*I want to find a list of perennials suitable for containers.  (Germany)
You'll find cultural summary, and lists of species in new leaflets on this site. Choose plants that will grow in proportion to the container, both in girth and height.  Plants should fill out the pot during the season, and be no more than 2 to 3 times as high as the container.  If plants are too small for a container, they wont fill it during the growing season, so may stay too wet.  If too short, they'll look add, and if too tall may need staking or be top heavy and blow over.  If they fit these size requirements, many perennials  may be used in containers.

 *I was given a peony by someone who only had a blood red peony in her garden.  When I planted it, the color was light pink to fuchsia.  Is there anything I can do to get this color? (New Jersey)
Probably not, except try another division or purchase one.  It sounds like perhaps the plant mutated as a result of some stress, perhaps division.  There is nothing you can add like with hydrangea to change the flower color.  I'd leave this one though and be patient, perhaps in another year it may revert back?

*I'd like to know when a plant is done blooming for the year, like a lily ....can you cut it down or should you leave it till it dies off ? (Wisconsin)
If separate flower stalks, like on daylilies or daffodils, you can cut these off (leaving doesnt hurt either).  If same stalk as leaves, as with many lilies, leave until stalk begins to die down--this way food reserves can still be made and sent to the roots while the plants is living and growing.

*Three years ago I was given a well established peony dug up from a friends garden.  Last year was the first time it bloomed for me - this year, only one flower - the plant is very lush, dark green and about 3' accross by 3.5' high (no sign of disease).  I give it a light organic fertilizer once a year and lime it at least once a year. It gets about 4.5 hrs of direct sun during the middle of the day - what can I do to improve bloom on this peony? (Vermont)
It sounds like you might need more sun if possible, or move it this fall.  Also make sure the crown with the buds from where the stems arise is only 1-2 inches deep.  Too deep and peonies often don't bloom.  Often bloom on perennials, especially early-season ones such as the peony, is determined by what happened last year.  But with a moist season in our area last year, most perennials are performing quite well so far this year and in fact many are loaded with buds and flowers.  So this doesn't sound like a factor here with your peony, but something to keep in mind for the future.

*What is your favorite perennial? (Iowa)
You've probably heard all the reasons one can't pick a "favorite" plant. It's like picking a favorite child--they all have their good and bad points.  Or, it's the plant I see at a particular moment!  But one of the many I like, and feel underutilized is the Helenium. It provides a mass of daisy-type flowers in mid summer to early fall depending on location (early in the south and UK, later in northern U.S.), 4-5 ft high and across (in moist years, as it likes moisture) of reds, oranges, yellows (depending obviously on cultivar).  A drawback is that this heavy mass often needs staking, but there are some shorter ones like Coppelia that dont.  Cutting back early, especially more so in the South, may keep plants shorter and avoid the need for staking.  It's been popular, and bred, in the UK and Europe (particularly Germany) for years and only now are a few more finding their way back home (most species are native to the U.S.).  I prefer the common name of Helen's flower (named after Helen of Troy, and reminds me of my mother of this name), to Sneezeweed.  The latter is such a misnomer, and probably reason it is not more popular here, with the ragweed which blooms at the same time causing allergies and not this one which people tend to notice and so think of as the culprit!
 

*There is a dense shade area by a corner of the house with no sun.  Hard to find something to grow here.  Hostas and hydrangea do OK.  I would like something else, but have had no luck.  Could it be the soil? (Ohio)
It is probably the dense shade and not the soil making it difficult to grow plants there.  Hostas are good for this, but watch for slugs.  Other choices for dense shade include ferns, barrenwort (Epimedium), astilbe, ginger (Asarum), deadnettle (Lamium), lily of the valley, lilyturf (Liriope, warm climates), spurge (Pachysandra), lungwort (Pulmonaria), foamflower (Tiarella), vinca, viola and barren strawberry (Waldsteinia).  For dry shade try hostas, epimediums, deadnettle, vinca, foamflower, viola and barren strawberry.

"Something" ate my Solomon Seals.  A rabbit?  Bugs? Creepy crawlies? What can I do? (Ohio)
Has your Solomon Seal resprouted?  If not, dig around the roots to see if still there, perhaps with buds, or just mushy and rotting.  Many perennials with this kind of damage early in the season will eventually resprout, or if late in the season resprout next year, so be patient.  Usually you see insects chewing on leaves.  If they have holes, and in such damp shade, it could be slugs.  If they disappear overnight like this, could be a larger mammal as you suggest like a rabbit.  See my leaflet on these pests and controls at http://pss.uvm.edu/ppp/pubs/OH52anml.htm

*Two articles from two different Extension Service offices state that most perennials do well in pH of 6.6 -7.0.  Another states they generally do best in 5.5-6.5. Can you put this issue to rest?
This is often the kind of contradicting or different results that you may find in references.  Actually in this case with pH or soil acidity, both are right.  Perennials are not very fussy in general about pH, a range of 5.5 to 7.5 being acceptable for most.  Of course some such as heaths and heathers "prefer" one lower than this, and some such as delphiniums, dianthus, baby's breath, lavender and clematis "prefer" the upper end of this range.  But the word "prefer" is key (and not one usually seen in references) as many plants grow outside their range of preferences.  Milkweed (Asclepias) is one that may have problems above 6.5, and many silver-leaved perennials prefer neutral to alkaline pH.  Rather than focus on pH, if within this range, make sure plants have good organic matter.  This helps "buffer" or resist swings in nutrition and pH. And make sure for most, that they have good watering in summer, and good drainage in winter.

*We recently had a devastating hail storm which destroyed all of our plants. What is the best way to care for plants which have been beaten down is such a manor? Should I cut them back? If so how much?  (North Dakota)
First, my condolences for your storm and plant loss.  I had one of these a few years ago, ripping my hosta leaves if not putting holes all in them.  With plants such as this or peonies that only grow once in the season, cut off any parts that are definately broken and will only die.  Rest, even though unsightly, can be left--just watch for signs of disease, and cut these parts off.  For other perennials (most) that might regrow, rebranch or recover, cut off the broken stems which again will only die.  If the plant tends to branch, cut back to the leaf nodes (where leaves join stems) where new branches will come out.  Some such as many perennial geraniums and perennial salvia can be cut back to either new basal growth, or to within a few inches of the ground if early in the season, and new shoots should emerge.  Some such as daylilies and iris, which are normally cut back to with 6 to 12 inches of the ground when divided, can be cut back to this.  They may not grow much this season, but the foliage will help build stronger roots for the following year.

*I wanted to know if I have to cut back my Purple Allium flowers?  They are huge, and I don't want to cut off the tops if I am not supposed to.  (Utah)
You are probably talking of the giant Allium (or globe allium), an onion relative.  All members of this family you can cut the flowers off after bloom, and in fact with many you want to in order to keep them from reseeding prolifically.  Just leave foliage to continue growth.  You can even keep the narrow foliage of some cut back (as with chives) as they regrow from the base.

*I have a retaining wall with springs keeping the soil damp in front of the wall. What are some good choices for a shady, moist soil ground cover? I have had luck with ferns.  (New York)
There are so many ferns to choose from, you could have a variety of heights, foliage colors and textures just of these.  Other choices might include primroses, astilbe, turtlehead (Chelone), barrenwort (Epimedium), globeflower (Trollius), marsh marigold (Caltha), even lowbush blueberry (Vaccinium).  There are many taller perennials as well for moist shade, including bugbane (Cimicifuga) and Helen's flower (Helenium).  If root invasive plants aren't an issue at your site, you might even consider the loosestrifes (Lysimachia) or variegated ribbon grass (Phalaris).
 

*My primrose leaves are very limp and falling off, some have black leaves. Doesnt look like it needs water. It has fertilizer and food. What's wrong? (Alaska)
If a plant like this has wilted leaves, yet plenty of water in the soil, it could mean that water isn't reaching the leaves due to a root disease such as from fungi, or stem disease such as from bacteria.  If the latter, not much you can do except toss the plant.  Check the roots though, and if the former, some should be mushy or discolored or darker than the usual white roots of most plants.  Remove the diseased roots, repot or replant the plant and keep on the dry side.  Hopefully new roots will form, and the plant will recover.  There are some fungicides for root rots, but often they are specific for the disease with not one chemical covering all.  Check with your local university Extension plant diagnostic lab, if one, or local Extension office, to see how to get this disease identified if the cultural treatments above don't work.
 

*Myholly hock leaves are turning brown and withering. There is enough rain so dryness is not the problem.  what can I do to save them?
 It could either be a leaf disease, or other disease to stems or roots (this could include other damage) that doesnt let water get from roots to leaves.  Most likely it is rust disease--you should see rusty spots on leaf undersides (yellow on top) that eventually causes them to yellow, wither and fall off, starting with lower ones first. Remove first infected leaves you see at beginning of the season. There are chemical sprays you can use, as well as some organic ones such as sulfur, but check with your local garden center.  Control often means frequent reapplications.  Usually mine get this, but still flower fine.  It is a common disease, and takes a lot of effort to control. Cut back infected parts after bloom and keep destroying any plant parts that get more rust, as it may overwinter on these.

*What is the provincial flower of Nunavut-- the new Canadian Province? (Ontario)
The arctic poppy (Papaver nudicaule) was proposed as the official flower at the 1998 Ottawa Tulip Festival. Nunavut is basically the eastern half of the former Northwest Territories, with mainly an Inuit population, and came into existence April 1, 1999.  Actually Nunavut is not officially a province, rather a territory, as are Yukon and Northwest Territories.  There are still 10 Canadian provinces.
 

* What would be a good perennial groundcover for wet soil and sunny? (Ohio)
 Is it a contained site--not near streams or waterways?  If so, there are some root-aggressive groundcovers like the Polygonums, Loosestrifes (Lysimachia) and mints, but if near water roots can spread downstream making them invasive.  Vaccinium or lowbush blueberry might be a good choice if a more woody perennial is desired.  Osmunda ferns and Siberian Iris are more tall and clumping, but placed close they provide a nice mass to cover the ground.

*What makes 'Blue Fortune' Anise Hyssop (Agastache) better than other cultivars?
This new cultivar from Rotterdam, Holland is a cross between two species.  It has the abundant purplish-blue flower spikes, 3 ft height, and long mid-summer bloom of its foeniculum parent (US native), and the hardiness at least to USDA zone 4 of its rugosa parent (Asian native)--so truly the best of both worlds!

*Before my lilies bloomed the leaves and buds turned brown. They bloomed, but not well. Why? (Virginia)
Probably drought. This is the main cause of such symptoms--too little water. If too wet and soggy soil, leaves and buds often just fall off and turn mushy brown, as they do from disease.

*What effect will this year's drought (second worst in East on record) have on my perennials? (several states)
Obviously for perennials just beginning to bloom, or not yet bloomed, they may not, or do so poorly, or bloom for a shorter period, or a combination. Perennials that bloom the first part of the summer set buds the following year, so the drought effects now will be seen on them next summer-- so expect such symptoms of poor bloom, including fewer flowers, next year on such as peonies, yarrow, spring flowers, and many daylilies and lilies.

*What are some perennials I can plant that will take drought like we've been having this year? (Massachusetts)
Some good candidates for dry shade include hostas, ajuga, vinca and foamflowers. For sun try tickseed or coreopsis, coneflower, sedum (low versions for rock gardens, tall ones such as 'Autumn Joy' for borders), and Black-eyed Susan (Rudbeckia). Of course the first few weeks, or season, when planted these should be kept well-watered until they become established--then they can take the drought.

*I have sandy soil, so my lawn and perennials have not fared well this year with the drought. What's the best solution? (Massachusetts, New Jersey)
You're right, sandy soils do not hold much water. Plants this past season in the East in clay or loamy soils have fared much better. So, short of installing plants that take the drought (see other question), or installing an irrigation system, you can begin improving the soil with organic matter. Small particle organic substances such as shredded leaves, sphagnum peat moss, or compost can be top-dressed (applied around) existing plants or worked into new beds. Be sure and use plenty--several inches a year for several years for really sandy soils (just be sure and don't bury existing plants!).

*What can I expect from my Baptisia plant the first year (it didn't bloom), and how do I prepare it for winter? (Masschusetts)
Hopefully you planted it where you want it, as Baptisia grow large (4 feet high and 6 feet wide) and resent moving. Keep it, as with most perennials, fertilized and well watered the first year. Like most perennials, it wont bloom the first year as yours apparently didn't (the pea-like flowers appear in June). After tops die back in late fall you can cut them off, or leave them until next spring. When plants bloom, they produce attractive black seed pods that make a nice rattle in the wind. This is a nice effect into winter, although leaving seedpods on fosters seedlings to be weeded the following year--so your choice! They are generally quite hardy.

*Should I cut back perennials in the fall?
Yes, definately if they have disease and be sure to not put the diseased plant parts in compost unless you can ensure the pile will get to 140 degrees F to kill the disease organisms. Otherwise, it kind of depends on your time available and desire. Obviously you will want to wait until after fall bloomers are through, such as Helenium and fall asters. If cutting back, leave at least a few inches of stem to help trap snow and provide some protection. Also, cut back as late as possible, in order to allow nutrients from the leaves and stems to cycle back to the roots-- perhaps late October in the north, late November in the south. On the other hand, I usually don't get around to it and cut back in the spring, and the plants are fine.

*How late can I plant perennials and bulbs? (several states including Alabama and New York)
Roots generally grow to about 40 degrees F soil temperature. This may occur in open soil about Nov. 1 in the far north and Dec. 1 in the upper south. And you want to allow ideally about 4-6 weeks for roots to grow and the plants to establish in the fall. Therefore early Oct in the north and early Nov. in the south are about as late as you should plan to plant out. Of course if you can't or don't get to it, you still may have luck planting later, but it is more risky. Earlier planting and more established plants, especially if small, provides more winter protection and less frost heaving in spring.

*Why didn't my tulips bloom this past spring? (Oklahoma)
There could be many causes such as wet soil, poor nutrition especially in previous years, shade, rodents, late cold killing buds. For those in the north, the season may be too short for bulbs to store sufficient food for good bloom the following year before heat comes and kills the tops back. In general, unlike some other bulbs like daffodils, tulips may be less vigorous in future years and may only bloom for 2-3 years. I and many others generally treat them as an annual, replanting yearly.

*Where can I find whether plant ??? is hardy in my area?
Start by checking at your local garden center or nursery. Also check on my links page, general category, for one of the plant search engines such as the one from Time Life. Type in your hardiness zone, or the plant name. Don't know your zone? Check another site at same general category for an interactive map for the U.S. There is another site with a map for Canada.

*Is there a discussion list for perennials?
Yes. There are also ones for alpines and plant propagation among others. ALWAYS send mail to majordomo@mallorn.com! Your message should contain the following two words of text:
subscribe perennials
don't forget to turn off your signature on your email if you have one.

*I didn't cut my perennials back in the fall. Is spring okay? (Ohio gardener)
Yes. I usually don't get around to mine, or am tired of gardening by then, or want to see the winter effect of many perennials, and also the stems helps trap snow for winter protection. The only time I usually cut back in fall is for damaged or diseased stems. Spring, just before growth (late April for us in USDA zone 4, week earlier for each zone further south)is when we cut back to about 6 inches above the ground. Then is a good time to check labels and relabel if needed.

*I am new to the area (any area, I've gotten this question from Alabama, Arkansas and Massachusetts among others) and want to know what to plant, what will grow well, and some designs.
This will vary so much with region, but in general good in most are peonies in early summer, daylilies in mid summer, hostas and coral bells for foliage and shade, and garden phlox and bee balm for late summer. There are many good sources of culture information on the internet-- check out my consumer leaflets page. For lists for specific requirements, check out the plant search engines and encyclopedias under General on my links page. For design, there's not much yet I've found on the net (let me know if you know of some sites) but there are many good books-- check your local bookstore, also book companies on the net such as on my links page (Timber Press in particular specializes in horticultural books.)

*When is the New England Flower Show? (Vermont)
Check out their site at http://www.masshort.org/fsfs.htm. Check out the "Virtual Boston" map, found through your favorite search engine, for directions. Also check out Flower Shows at the Garden Web, located on my links page.

*What affect is this winter having on perennials? (Minnesota)
It's hard to say obviously until spring. The fairly mild winter in New England (1997, also 1998) should be good for them, until recently when wide temperature fluctuations melt snow, provide rain, this freezes when temperatures drop again, and so the lack of snow cover allows soil temperatures (what is more critical than the air temperatures for non-evergreen herbacous perennials)to drop to perhaps damaging levels. How low they drop, and how long they stay there will determine whether the perennials are injured.

*I have a serious problem with voles. I have tried many methods of ridding my garden of them while they continue ridding me of a garden. Any suggestions? (New Jersey--I get this question from all over, and have a problem myself in Vermont.)
I too have a similar situation and have tried many supposed remedies including expensive sound emitters and solutions you pour on the soil (basically castor oil). I don't like poison baits as they tend to work up the food chain and may kill domestic pets too. The only remedy I seem to have any luck with is a spring-type trap, baited with peanut butter, placed at their holes, with an inverted clay pot over the trap and hole (makes them think they're still underground). Cats also work, but I find you need two to compete. Just one often tends to get bored and slack off on the hunting!

*My lawn has several birch trees and the grass has turned to moss. I would like to gradually replace the grass with flowers and ground cover. Not too expensively and I would like to do the work myself. I am a new gardener. (St. John's, Newfoundland)
You have a common problem to many. One option would be to live with and enjoy a "moss garden", interplanting some ferns for texture and a few accent flowers for color like annual impatiens or perennial hostas for bold texture or perennial astilbes for color. A groundcover which should do well is periwinkle or Vinca minor. Daffodils should also provide nice color and do well naturalized in such an area for early spring color. You should also check out the various search programs on my links page-- general section. One is by Time Life. You can input your zone, conditions like shade, and it will come up with a list of the many other perennials for shade. Moss is usually a sign of moist soil, organic soil (both good), shade, or low pH (raise by liming per a soil test).

*When is the Vermont Flower Show, and who is speaking? (New York)
For dates and details, and schedule a month before, see the web site at http://pss.uvm.edu/vfs/vfs.html

*I didn't get my bulbs planted in the fall. Is early spring okay? (Illinois)
Probably not, but for most bulbs which require cold you don't have much other option from mid-winter on. Earlier (late fall, early winter) you can plant in pots, keep at 40F for 3-4 months for their chilling requirement and rooting, then force indoors. Or you can plant out in spring as you would a potted plant. Even if bulbs get their cold as in a refrigerator, if they aren't planted until spring they will immediately start growing tops, without much roots, and so wont survive very well.

*Do you have any suggestions on where and how to buy good plants? (Vermont)
When buying plants, I always try to buy perennials in full bloom. I know, you're probably thinking, as an experienced gardener why-- you know what the blooms will look like? "Will" and "should" are two different things. I often find plants mislabeled, often through no fault of the nursery. This is also one reason I don't buy from the mass marketers-- often they don't know or often care what the labels say.

If a woody plant, it is easy to get the bare root plants from their suppliers in storage or shipping mixed up, and similarly for perennials. Or well meaning customers remove a tag to read, then put back on the wrong plant. (Try not to do this when shopping, speaking from experience!) After wanting a red this or yellow that for a specific purpose, and getting the wrong plant, I have come to this policy. The times I don't follow this are when buying from a very reputable local nursery that grows their own plants, or if buying the plant mainly for foliage. Often a good guide is a nursery that is a member of their state professional association, and has employees who have passed one of the many certification programs held by such associations.

Also, even when buying in color, I have to keep in mind that what I'll mainly see with perennials-- both woody and herbaceous-- is foliage, so must keep this in mind. The problem I've had with buying in color, is that for the first few years of gardening I never seemed to have time to get out to nurseries until later in the season-- hence my garden turned into mainly late blooming varieties! I've in recent years had to concentrate on either getting out sooner to buy, or buying those varieties which bloomed earlier in the season.

*I always have a problem keeping plants labeled. Do you have any suggestions? (Massachusetts)
As I've heard other experienced gardeners say, "the only thing worse than a plant without a label, is a label without a plant." I've learned you can't put this off, and must be religious-- get in a yearly or more often habit-- about label maintenance. Now when I get home from the nursery with new plants I immediately make a more permanent label of my style and put in the pot so it will be there when planting. I've found I can get a year out of a plastic label, and that #2 pencil is about the only medium that wont wear off in that time. I could get longer out of metal labels but don't use them for 2 reasons-- the year cycle forces me to once a year visit every plant to check on it and replace the label (I need this incentive with over 1500 perennials), and with so many plants can't afford the more expensive labels (I do use them in more limited display gardens vs. trials).

When I make the label, I also enter the plant on a list, which during the long winter months of Vermont I enter on the computer plant list. I also use this time to make up, by bed, all the labels for the coming year. And another tip-- when planting, if a whole bed or several varieties of the same plant-- make a map! I've lost too many plant identities with labels getting removed or just moved as in weeding to do otherwise.

*Do you have any suggestions for how to keep up with the weeds? (New Jersey)
If you have weeds, there is a reason. Something is wrong with your culture. Weeds have a purpose, such as the tap rooted ones drawing up nutrients from the depths to the surface of impoverished soils. The main problem is that nature doesn't like bare earth, and preferably likes it covered with green foliage. So when planting I make sure I mulch heavily (organic) for the first year or two until plants are established. The goal is to then have total coverage of the earth from the desirable plants, which greatly minimized my weeding. I have friends and know gardeners who like discreet and individual plants with nice bark mulch between. There is nothing wrong with this, just realize that such culture means keeping the mulch between plants thick and more maintenance in weeding.

*I have white disease on the leaves of my garden phlox, monarda and other plants. What can I do about this? (Pennsylvania)
What you have is powdery mildew disease. It is basically favored by humid or damp weather and moderate temperatures. Air movement, such as from thinning stems and wider spacing often helps in landscapes. There are also chemical sprays you can use, and horticultural oil is also an organic option. The best solution is to plant resistant varieties to begin with. See my research on this and slides shows, under the sustainable research page, for much more on this disease and management.

*How can I keep stray cats from digging in my perennial garden? (Delaware)
Many catalogs and garden stores offer dog and cat repellents you can put around the garden. Physical deterents such as chicken wire placed on the ground, above or under mulch, around desirable plants are effective but rather cumbersome to install sometimes. Mulch which cats may not find conducive to digging, such as marble or brick chips, may also be effective (depending on the cats and their desires!). Of course other options would be to discuss with cat owners (if known) keeping their cats under control (some towns have pet ordinances), or fences.

*How can I eradicate grasses that are growing among my spreading junipers? (Minnesota)
You have a good question-- one I have a problem with too, only with creeping phlox. There are some grass herbicides which only kill grass, not broad-leaved plants. But make sure to read the label and follow directions, and make sure the plant you want to save wont be injured. If it doesn't mention your desirable plant, it is always safer to try on a small area first just to make sure. My solution though as I tend to try and avoid such herbicides, is to dig up my phlox this year and either weed and replant, or replace with new varieties (actually what I've been meaning to do for some time now). It's a bit harder with plants such as junipers. I've had good luck with these though just putting on some long sleeves and gloves (to avoid their pricky foliage) and pulling back the branches to weed underneath. And I've learned from my own experiences to make sure the soil is grass or weed free before planting!

*How can I get rid of whiteflies? (Hamilton, Ontario)
First, make sure you have whiteflies--they're pretty easy to see-- bascially white flies that swarm when you move plants. I always start with a soap based "organic" pesticide, which you mentioned has quit working for you. There are a couple other whitfly products such as with resmethrin as an active ingredient, but you have to make sure they are labeled in your case for vegetable use-- with food crops in greenhouses it can be very tricky to control such pests. Often a soap-based product is about the only remedy, and often the insects in their many and quick generations develop resistance to a particular pesticide. So if you find one that works, alternate with another about every 3rd or 4th time. Check your local garden stores to see what else they may have-- I'm always on the lookout when traveling for a different safe product or two I can add to the arsenal! For many insect pests you may also investigate the use of predator insects or diseases-- biological controls. There are more each year. Check some of the links on my sources, products section from my links page.

*With all the rain from El Nino this year, are the black spots on my leaves a disease? (Los Angeles)
This definately could be a fungus if you haven't seen these before. You might take a few leaves to your local garden center to be sure though and ask them-- also if so, while there, they can prescribe some control I'm sure. Or check with your local land grant or state university, as most have a plant diagnostic clinic. (Your local Extension office also often helps with diseases, or leading to such clinics.) Some plants though, like your impatiens, when they get too much water exude the excess through their leaf pores (stomates) and often form "water blisters"-- this is called oedema. These can then discolor, forming "leaf spots" too. The only control for the latter is to try and keep the soil drier. This problem is usually seen with annuals and houseplants, and not too often with perennials expcept perhaps in a humid greenhouse.

*With the mild winter my daffodils starting coming up early this year. With the late snow and cold, will they be injured? (Vermont)
As with many answers, "it depends". If they only had an inch or two of leaf tips, with the more tender buds still deep in the ground, probably not. If you can see a swelling at the base of the leaves (buds) and leaves are several inches long, probably so. If you have several inches of mulch, and leaves are just emerging, probably not. If bulbs are in a protected place as near a warm foundation, or covered with at least several inches of snow during late cold, probably not. If in doubt, you can always shovel some snow on them, or add some straw (not weedy hay) around them (or even pine straw or other such loose materials) to provide additional protection.

*I would like to grow Lenten Rose (Hellebore) as a groundcover for shade, but can't afford to buy the expensive plants. Can it be grown from seeds? (Massachusetts)
It can, but like many perennials, the fun is in the cultivars (cultivated varieties) which often don't come true from seed. If you're willing to see what you get, and wait (often this takes 2 years or more to germinate), give it a try. These seeds often have "double dormancy", meaning they need to be sown and kept moist and cool (40F), warm (60F), then cool and warm again, each for about 2-3 months--hence the 2 years. The Hellebore or Lenten Rose is quite popular now, with many new cultivars, but keep away from children as it is poisonous.

*I'm a new gardener and would like to grow some perennials from seeds. Which would you recommend? (Connecticut)
First keep in mind that the excitement with many perennials is the cultivars (cultivated varieties), and that many of these can't be propagated from seeds for the young to resemble the parents. So if interested in these named cultivars, check your local garden center or many mail order catalogs now sell small plants (plugs) of many (see links page, sources section). Some easy perennials which are fairly reliable from seeds, and which you might try, include Columbine, Coneflower (Echinacea), Early Sunrise Coreopsis, Black-eyed Susans (Rudbeckia), Shasta Daisy, Delphinium, Hollyhock, Lupine, Oriental Poppy, Primrose, and Speedwell.

*What do you recommend as good labels for the perennial garden? (Virginia)
It really depends on several factors-- your climate, microclimate, garden ethic, budget, number of plants, etc. There are some nice metal labels on short stakes you can write on with special pencils-- very nice, but expensive if you have hundreds of perennials like me. On the other end are the wood labels, or even popsicle sticks. Either pencil or permanent marker works on these, but these stakes will rot in a year or so and the names may be "sandblasted" off if windy. Although I'd rather not use plastic, I find I get at least a season from them, and pencil lasts the whole year (even in a hot sunny rock garden, or with our cold Vermont winters) while "permanent" marker does not . Plastic will crack after a year or so, and need replacing. I make up new labels during the winter from my master list (another good idea if you can get organized). Caution, when using permanent markers, use only black, as the colored inks usually only last a few weeks before they disappear! Of course check your local garden stores or catalogs for many other labels available that might suit your needs.

*Is there a good computer program to help pick plants and keep track of them? (Washington)
There are several software programs, many available at your local bookstore or computer software store, to help pick and design flower gardens. As for keeping track of your plants, this is easily done on databases that come with most computer packages or bundles. One that came with my laptop-- Microsoft Works-- is the one I use, just setting up fields as I need them for scientific name, common name, year in, year died, bed, etc. You can then pick by a certain trait, such as by bed, and organize such as by common name. Others that are more sophisticated but common include, but are not limited to, Access and dbase.

*Do you know what varieties of lotus might survive moderately cold Dutch winters? (Netherlands)
As I don't have specific experience with cultivars of this plant, you should check some of the source links from my page on links, sources section. Many of these have some excellent cultural information as well as listings. I do know the species in general is listed for your winter temperature range (zone 6, 0F/-20C), especially if located deeply in a pond below the frozen ice layer. It seems a key issue though for you is heat in summer-- apparently this is needed for good bloom. A deep pond site obviously would survive winter better, but not provide as much heat as a shallow one. So it almost seems like additional heating of the water in summer might be needed. If you had a raised bed, especially of dark color or material, this should be warmer. Or perhaps you could rig a dark or black barrel to absorb and heat water, which could then be slowly added to the pond.

*Something is eating my hosta leaves. What is it and what do I do? (Indiana)
Usually with hostas (funkia, plantain lily) this is caused by slugs feeding at night. Check out my slug web site (yes there is one for most anything) on my links page. Many have success just putting a board in the bed which they crawl under during day, and you can then find and remove them. There are poison baits, but these can kill domestic pets as well. The most popular remedy is saucers of beer, which attract slugs, and then they drown. The most effective though is probably copper strips-- slugs wont cross them as they get shocked. Keeping lower leaves off for more ventilation, and mulch removed for less dampness, help as well.

*How can I overwinter tender perennials? (Toronto, Canada)
I usually bring them in in pots and overwinter indoors in a cool area such as cool (above freezing, below 45-50 degress) greenhouse, garage or hallway with window-- including some salvia, lobelia and some grasses such as the Red Foxtail (Pennisetum). Often I just leave these in pots during the growing season, sinking the pots in the ground either with or without another pot. The advantage to the "pot-in-pot" system is ease of changing plants, as you might change your furniture. This way you can keep plants in bloom in an area, rotating in new ones to replace finished ones. The down side is that they get little moisture from the soil and require more frequent watering, which an automatic system with drip tubes to each pot or emitters can help. Tender plants may also be overwintered by covering with overwintering blankets (may be hard to find) or the styrofoam cones usually used for roses. These may provide some insulation, but the best insulator is snow.

*This season my wooden stakes rotted. Is there anything better to use? (Vermont)
My wooden stakes rotted too with all the rain, and I always have to replace them yearly anyway. So this year I'm trying a method I saw at Longwood Gardens-- rebar. This is the reinforcing metal rod used in concrete, and available from most lumber and home building stores. I find 4 or 6-foot lengths most useful, depending on the plant (4 ft. for peonies, 6 ft for asters for instance). I drive these 2 feet into the ground. For a bed with many delphiniums, I put in several, then weave twine between creating a mesh for the plants to grow through. I also have used wise-mesh fencing, cut to make cylinders a couple feet across and placed over plants in early spring. These can be held in place with the rebar as well. I have also seen the very wide mesh wire screen, again used to reinforce concrete, used for cylinders to put over plants. Not only does this rust and blend in with the landscape, but it is sturdy enough to not need additional staking.

*This year I had quite a problem with deer eating my perennials. What can I do, and are there any resistant plants? (upstate New York and others)
There are some methods you can use, depending on the severity of the population, and some plants the deer tend to avoid. See my leaflet at http://www.uvm.edu/~pass/perry/oh64.html for details.

*I'm new to growing perennials, and wondered if there is a good book on color to help me design with them? (Massachusetts)
Yes, in fact there are a couple books new in 1998 just on this topic. These are reviewed on my Publications Pages. Of course there is treatment of this to varying degrees in many general perennial books and books on perennial design as well, several of which are also listed on the above page.

Didn't find your question answered above? Please leave your question on the comments form, or try (if a U.S. resident),  your state Extension Service.  There are also several websites answering questions, some linked here.  Let the asker beware though of the knowledge of unknown "experts" or those without some credentials, especially if not in your geographic area.
 
 


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