University of Vermont Extension System
Department of Plant and Soil Science

Dr. Leonard P. Perry, Extension Professor

What are Perennials?

• lives from year to year, more than 2 years
• by definition includes woodies, by usage refers to herbaceous
• whether it's a perennial, wildflower, weed--depends on our desires
• generally tops die back to ground in winter
• often blooms second year and after
• average 3 week bloom period, so plant structure and foliage is important

• annual: completes life cycle from seed to flower in one year, then dies
• function of location--perennials in south may be annuals in north (and opposite)
• trend: use tropical perennials as annuals in northern gardens
• design tip: mix some annuals with perennials for continuous bloom

• great variety of plants, blooms, foliages
• don't plant every year, so less expensive
• ability to specialize in plant groups, societies
• more of a challenge to combine well

• do have to divide every 3-5 years on average
• short period of bloom, mainly look at foliage
• often less striking blooms
• too much challenge for some--too many choices, design over time

• Bed types: walks and streets, foundations, corners, borders, island or free-standing, slopes, groundcover for sun or shade, under trees, containers, raised beds and containers
• Functions: aesthetic, physical, wildlife, edible, herbal, scent
• Themes: country, period or historic, literature, children, wildflower, water, evening or night or moon, model train, rock or alpine, plant type, whimsy
• Ecological Plant Habitats: open, shade, damp, dry or xeriscape, seashore, meadow, woodland, rocky, sandy or clay, other...

• Traits: choose plants to fit site, not alter site to fit plants
• non-impacting on surrounding environment
• good for wildlife
• diversity of plants
• Results: fewer major problems, sustainable, lower care and maintenance

• mostly sold in pots, can be purchased and planted all season
• usually less root damage, no need to cut back, quicker to establish
• if root bound, separate roots before planting
• more different pot soil is from native soil, slower may be establishment
• bigger the pot, more roots, more expensive, but more instant effect
• small pack plants cheaper, need more care to establish, may not bloom first year
• bare root more for growers, or large tough perennials (peonies, daylilies)
• if fiber or husk pots, keep well-watered and plant soon

• Since in one place several years, key to prepare well in beginning
• key ingredient: weed free compost, for any soil type sand to clay
• sand is much less effective for clay soils, may destroy porosity
• site with good drainage, or watch plant choice (drain tiles as last resort)
• spade 8-12 inches, remove rocks, add peat moss
• soil test: main interests are lime (pH 6-7), phosphorus (P)
• if no soil test, add at planting:
• rock phosphate or superphosphate, 3Tbsps per bushel, avoid bone meal
• 5-10-5, 3 cups per 100 sq.ft.
• lime, 7 cups per 100 sq.ft.

• varies with plant, location--consider when reading references
• most in north grow and bloom best in sun
• some tolerate shade (daylily), some prefer shade (hosta)
• some that prefer shade, tolerate sun, IF sufficient moisture (astilbe)
• most for shade like part or filtered, not dense shade

• divisions, bare root--varies, but generally early spring as growth under 6 inches
• containers--any, best until early fall (early-mid September) so roots establish
• water especially well if in summer
• remove tops of fiber, peat pots if not whole pots
• more different pot soil is from native, larger hole and more organic matter
• same depth as in pot

• 1-3 ft. depending on
• mature plant habit, size
• how soon want to mature--closer give quicker effect, but more care
• groups, odd numbers, (3,5,7...), generally staggered or informal pattern

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture.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.

version 3/21/01