Leonard P. Perry, Extension Professor
Choosing the proper container, growing mix, and culture is important for success with growing herbaceous perennials in containers, and has been covered elsewhere. Also important of course is the proper selection of perennial species and cultivars.
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 (in addition to the list below) may be used in containers.
If using several plants together, choose ones that not only look good, but wont crowd each other out. A low spreader might be okay, trailing over the side of a pot, but other aggressive plants may kill out the weaker ones. You may also consider plants to combine that bloom in different months. And of course combine plants with similar cultural and soil needs.
Another solution to having bloom through the season, especially if plant combinations in large containers aren't possible, is to use the "pot in pot" method. Grow a variety of perennials in any sort of pots, even inexpensive and unattractive nursery pots. Then sink these into wider, more attractive pots. Fill in with some organic material such as potting mix or compost, which will hold moisture and cover the inner, unattractive pot. In this way plants can be rotated out when done bloom, and others in. These perennials in pots can then be all sunk in the garden the end of the season for overwintering. If aquatic plants, these may be treated as annuals, or overwintered in tubs of water, or just kept moist, in cool spaces indoors. Bulbs can be potted in the fall, sunk in the ground, the pots dug in spring when shoots emerge, and then the pots sunk into larger containers as above. Tender bulbs may need more protection over winter (see other references for bulb choices).
For the following perennial groupings, some species and cultivars may
be shorter and more suited for containers. Others not listed may have dwarf
cultivars as well that would be appropriate such as with Boltonia, Echinacea,
Monarda and Solidago. Alpines are suited to trough gardens,
and are not covered here. Keep in mind above points when matching cultivars
to pot size. Some late season perennials such as Aster novae-angliae,
Helianthus and Solidago may be pruned once or more early in
the season to result in shorter plants more suited to containers. Those
marked (psh) tolerate part shade better than most, although may bloom best
in sun (especially in northern climates).
Dicentra spectabilis (psh)
Phlox (some) (psh)
(generally 1-3' unless noted)
Festuca (under 1')
Dicentra eximia (psh)
|Perennials--late summer, early fall
Aster, dwarf cultivars
Sedum (and related)
Solidago, dwarf cultivars
Acorus (e) (w)
Iris (some) (w)
Iris pseudacorus (e)
Iris versicolor (e)
Nasturium (watercress) (e)
Phalaris (e) (w)
f=floating, e=emergent, roots in soil below water, w=wet, boggy soils
Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. Lawrence Forcier, Director, UVM Extension System, Burlington, Vermont. University of Vermont Extension System and U.S. Department of Agriculture cooperating, offer education and employment to everyone, without regard to race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status.
Last reviewed 9/20/01