University of Vermont
Department of Plant and Soil Science

gmg logo Summer News Articleline


Leonard Perry, UVM Horticulturist
and Charlie Nardozzi, Garden Consultant

Choosing hostas, watching for powdery mildew, and netting blueberries are some of the gardening activities for this month.

If you’re having trouble choosing hostas (aka plantain lilies) for your garden, faced with the hundreds available in all manner of sizes and leaf colorations, then look to the winners from the American Hosta Growers Association (  Their 2016 Hosta of the Year is called ‘Curly Fries’.  With a name like that you can envision this mounding, short (one foot or less high) plant, with narrow and highly ruffled leaves.  The leaves are yellow when they emerge, then turn whiter with age.  In mid to late summer, purple flower stalks (“scapes”) produce lavender flowers.  To add to the fun of the name, one of the parents of this hybrid is ‘Pineapple Upsidedown Cake’.

At the first sign of powdery mildew on phlox, bee balm, and other susceptible plants, treat with Serenade or other labeled fungicide, such as one with potassium bicarbonate (relative of baking soda).  Spray plants every two weeks, thoroughly wetting the foliage.
Birds love blueberries as much as we do, so protect the fruit with netting.   Use stakes to suspend the netting over the shrub so birds won’t reach the berries. Secure the netting to the ground to prevent birds from sneaking in. Get your cover in place before the berries turn ripe.

Stop pruning most trees and shrubs now, and allow roses to form hips. Pruning, similar to fertilizing, stimulates new growth that may not have time to harden off before the first cold snap of autumn. Leaving spent rose flowers so they form hips signals roses that they, too, should begin winding down.

Continue planting vegetables such as radishes, carrots, and lettuce so that you'll have a continual supply of these vegetables into the fall. Seeds will germinate quickly in warm soils, but so will the weeds. Be diligent about weeding, watering, and thinning your new seedlings.

If you're going on vacation and are concerned about your container plants, here are some tips for keeping them healthy. Water containers thoroughly before leaving and move them into a shady location where they won't dry out as fast. Place smaller containers in basins with a few inches of water that will slowly be absorbed by the plants while you're gone.  If you’ll be gone for a longer period, line up a plant sitter but make sure you go over with them all the details you want done.  Grouping potted plants makes it easier for your sitter to not miss any.

Most gardeners know the perennial delphinium with its showy flower spikes, typically in shades of blues from five to eight feet high.  Yet you can find shorter selections, or ones with rosy pink or white flowers.  You may even find some species with red, orange, or yellow flowers.  Flowers of some selections have white or black centers, known as “bees”.  Each year the National Garden Bureau chooses a Perennial of the Year, and for 2016 it is the delphinium.  You can learn more about this and other plants of the year at their website ( 

Summer is a great time to visit perennial nurseries to see what is in bloom, and add to your collection.  As virtually all perennials are in pots, it is fine to plant them now, just add some compost at planting, mulch, and keep them well-watered.  A good place to begin your search for local Vermont sources is the online nursery listing from Green Works (

(Charlie Nardozzi is a nationally known horticulturist, author, gardening consultant, and garden coach;

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