A perennial, by definition, is a plant that lives for three or more years. This would stretch
from dandelions to redwoods and many species in between. When gardeners refer to
perennials, they mean flowering garden plants with herbaceous stems. These
plants die down to the soil's surface in winters while the root remains alive
and ready to send fresh growth in the spring. The durability of the roots sets
them apart. They come up unprompted year after year and set the garden ablaze
with color from April to November. Perennials flower abundantly and multiply
without being coaxed. They are easy to grow and tolerate considerable neglect.
Perennials include delphiniums, columbines, daisies and peonies.
Annuals sprout from seed, bear fruit, seeds and flowers and die – all in a single year.
Biennials spend their first years growing, produce flowers and seeds in the second year- and then die. Sweet William, foxglove, Canterbury bell and wallflower are some of the common biennials.
Flowering perennials are noticeably long lived. The first recorded appearance of peonies dates back to 1864. Delphiniums thrive for seven to eight years where summers and winters are moderate. Day lilies, coreopsis, acanthus, lavender cotton and false indigo grow beautifully in a warm and humid climate. The dry and windy places do not lack for perennials. Oriental poppies, garden phlox, bearded irises, day lillies, chrysanthemum and many others flourish there.
The first challenge while growing perennials is to obtain continuity of color by planting various varieties to flower at different times. The aim is to present a charming array of color from early spring to late fall. However, a rare perennial flowers all of the growing season.
Another problem is to keep the assorted perennials from overgrowing one another in the beds and creating a mess. Some perennials like chrysanthemums spread so fast that they require drastic control methods like annual digging up and division of the roots. Others never outgrow their allotted space. Therefore, the planting has to be planned well in advance taking the characteristics of the various plants into consideration.
The third challenge while growing perennials is to obtain maximum results with minimum work. Good perennial gardens require plenty of air circulation. Stagnant air encourages plant diseases especially in humid places. They require abundant sunshine. Day lilies, columbine and leopards bane will tolerate shade whereas some like Japanese anemone, plantain lilies, yellow corydalis, western bleeding heart and Siberian bugloss will thrive in it. However, the majority will sprout spindly stems with few flowers without ample sun.
Finally, good perennial gardens require well-prepared soil. The soil should be moisture retentive as well as well drained. It should be rich enough to sustain the plants for many years and should be loose enough to permit air and water to reach the roots.
Not all gardens have all the characteristics. Given the air circulation and the sunshine, the rest can be prepared. Once the garden area has been finalized, you can move onto planning the type and location of the various plants.