Flowering plants fit into many different categories and classifications, from foliage type to lifespan or blooming period. One of the most helpful things to know when you go to select flowers for your garden is the lifespan of a plant. Flowers can broadly be categorized as annual, biennial or perennial.
Annuals are plants that finish their life cycle in one year. Annual flowers are frequently used for spring and summer flower beds, which offer bright, short-term bursts of color. Many gardeners grow plants that are perennials in warm climates as annuals. These flowers are planted in the spring or summer and then dug up or left to die in the first winter frosts.
Popular annual flowers include the California poppy (Eschscholzia californica), a cup-shaped, orange wild flower that is the state flower of California, the zinnia (Zinnia elegans), a brightly colored member of the daisy family, and the marigold (Tagetes spp.), a fiery orange or yellow flower that's well known for its resistance to pests.
Biennials, also called short-lived perennials are plants that complete their life cycle in two years. There are considerably fewer garden biennials than there are annuals or perennials, but there are many popular biennials that most gardeners have worked with at one time or another.
Common biennials include the black-eyed Susan (Rudbeckia hirta), a low-maintenance yellow and brown flower native to North America, the common foxglove (Digitalis purpurea), an upright flower with tubular blooms, and the evening primrose (Oenothera caespitosa), a low-growing summer blooming flower. Enjoyed for its many patterns and colors, the pansy (Viola x wittrockiana) is a garden hybrid biennial that finds its ways into most gardens at some point.
Perennials are plants that have a lifespan of more than three years. Though technically trees and shrubs are perennials, the term is usually reserved for herbaceous plants rather than "woody" plants. Perennials are valued for their practicality, as plants do not have to be replanted year after year. Perennials grown from bulbs are often left in the ground during the winter, or dug up and stored in the fridge or in a cool dark drawer until they can be replanted in spring.
Popular perennial flowers include the colorful gerber daisy (Gerbera Jamesonii), a daisy species native to South Africa, the calla lily (Zantedeschia aethiopica), a funnel-shaped flower accented by fleshy foliage, and the tulip (Tulipa spp.), a cup-shaped member of the lily family.