Let's start by dispelling a common beginner gardening myth: You don't need to be an expert gardener to grow perennials. Many types of perennials are easy to grow and provide years of pleasure with minimal upkeep.
Here are answers to a few common questions about perennials.
Plants are classified as either annual, biennial, or perennial. Annual plants live for only one growing season, during which they produce seeds and then die. Familiar annual plants include impatiens, zinnias, and sunflowers. Biennial plants, such as some types of foxglove, live for two growing seasons before setting seed and dying. The term perennial is reserved for plants that live for more than two years; examples include daylilies, hosta, and peonies.
Technically speaking, trees and shrubs are perennial plants--they live for more than two years. But in common usage the term perennial refers to herbaceous perennials: non-woody plants that die back to the ground each fall, then regrow in spring.
If you grow lots of annual flowers, you are familiar with the chores necessary to maintain the plantings: You purchase flower seedlings (or start your own), plant them in spring, and nurture them throughout the growing season. Then, when the season's over and the plants die, you pull them out. Next spring, the cycle begins anew.
Perennial plants remain in the ground year after year. Once established, most perennials need minimal upkeep in the form of watering and fertilizing, since their roots are more far-ranging than those of annual plants. Many perennials spread readily, filling out garden spaces and providing more and more color each year.
Most perennial plants have a distinct bloom period, lasting anywhere from a week to a month or more. Plant descriptions usually include an approximate bloom time, such as "early summer" or "autumn." A few will describe certain plants as continuous bloomers, but even these usually have a period of peak bloom.
At first, this may seem like a drawback, since each plant won't flower all summer. However, properly planned, a perennial garden will have flowers all season long--they just won't be the same flowers all the time. Perennial gardens change with the seasons. You can enjoy delicate columbines in the spring, flamboyant peonies in early summer, stately delphiniums in midsummer, and cheerful black-eyed Susans in late summer right into autumn--all in the same flower bed. One of the greatest joys of perennial gardening is watching the plantings change with the seasons.