Contact: Dr. Leonard Perry, Extension Professor
University of Vermont
Perennials can provide a long sequence of bloom if plants are carefully selected. Very early bloom can be obtained by planting spring flowering bulbs with perennials. The peak perennial bloom comes in June and July with a scattering of bloom ending with the chrysanthemums in the fall.
The beauty of perennials is that once planted, they come up every year for a number of years. The life span of a particular planting of perennials will depend on the soil type and the care the bed receives.
Perennials planted in poorly prepared soil may last only one year. A good perennial site has excellent drainage and protection from drying winds.
Perennial bed preparation should begin the year before the bed is to be planted. Check the drainage and make soil improvements if needed by adding organic matter. Deep soil preparation is important for perennials because the plants will be in place for many years.
Select compact and dark green plants. Plants held in warm shopping areas often have long, pale green growth and are not as suitable as seedlings or completely dormant plants. Named varieties are best because their ornamental characteristics are known.
Plants grown from saved seed may be different than the plant from which the seed was collected. Many perennials do not produce true from seed. Seed saved from garden phlox, for example, may produce plants with muddy pink flowers.
Plants purchased from catalogs may arrive as small divisions or root cuttings. These have a better chance for survival if started in pots to be transplanted later.
Perennials vary in size so when setting plants in the garden, be sure to space properly to allow ample room for growth. Overcrowded plants are more subject to disease problems.
Do not leave plants sitting around after buying them. Plant them as soon as possible. Remove plants grown in containers with individual compartments for each plant by gently flexing the sides. Tear off the tops of peat pots, or bury completely at planting time. Any portion of a peat pot sticking out of the soil will act like a wick and dry out the rest of the pot. Set plants at the same level they grew at in the flat or container. Water well.
Perennials need summer watering, preferably infrequent, deep waterings. Apply an inch of water each week, or as needed, depending on soil type and amount of natural rainfall.
Start watering in early morning, ending early enough so plants dry off before nightfall. Evening watering means wet leaves, which combined with cool night temperatures, make disease development easier. Avoid daily light sprinklings with a hand held hose.