Perennials, says Texas A&M University, are plants that live for several growing seasons. The visible parts of most perennials die back during the winter, but their root systems remain viable and new growth appears each spring. Some perennials, however, keep their leaves even in winter. Perennials may be woody trees and shrubs, herbaceous flowering plants or bulb plants. Perennials planted from seed bloom in their second year. Propagating them by plant division may produce quicker flowering.
Spring-blooming bulb perennials include daffodils (Narcissus), crocus (Crocus vernus) and hyacinth (Hyacinthus orientalis). All of them need cold winters to stimulate their blooming cycle. Plant them among carpets of moss phlox (Phlox stolonifera) and early spring bloomer that covers the ground with star-shaped blooms of white, pink, blue or lavender above evergreen foliage.
Peonies (Paeonia lactiflora) are herbaceous perennials and among the showiest plants of any season. Standing up to 3 feet high and wide, fragrant peony cultivars come in a variety of colors. Deep green foliage contrasts well with other flowering plants when peonies finish blooming. Undisturbed peonies will perform for decades.
Mock orange (Philadephus microphyllus), blooming in early summer, is a perennial shrub reaching up to 15 feet high with an equal spread. It's named for the large, fragrant white blooms that resemble orange blossoms. The June Bride cultivar, up to 6 feet high and wide, has small green leaves and reddish peeling bark
Growing from 1 to 8 feet high and up to 2 feet wide, hybrid lilies (Lilium) are bulb perennials blooming from June to August. They have straight stems with narrow, green lance-shaped leaves. Lily cultivars come in a range of colors from pure white Bright Diamond to nearly black Landini. Many have exceptional fragrance or unusual markings.
Heath aster (Aster ericoides), is a 1-to-3-foot herbaceous perennial, blooms in September and October. Blue Star aster has tall stems with abundant tiny blue yellow-centered flowers similar to daisies. Heath aster is a good addition to butterfly gardens, but may need staking.
Hardy impatiens (Impatiens omeiana) is a shade-loving native of China capable of handling winters in USDA Hardiness Zones 6 through 9 (minimum temperatures of minus 10 degrees F). Its yellow blooms, resembling snapdragons, appear above deep-green elliptical leaves in September and October. Plants stand up to 18 inches high and wide.