Garden flowers can be classified into three basic groups: annuals, biennials, and perennials. This method of classifying garden flowers is based on the amount of time it takes them to complete their life cycle. Garden flowers sprout from seed, flower, produce more seed, and die in one or more growing seasons.

Annuals are garden flowers that complete their life cycle within one year or growing season. Because they bloom quickly and are generally grown from seed, annuals can add visual appeal to your garden almost instantly and economically. Planting annuals allows you to change the appearance of your garden every year. Annuals may be further classified according to their tolerance to cold weather and frost, using the terms “hardy,” “half-hardy” and “tender.” Hardy annuals are garden flowers that can withstand cold temperatures and moderate to light frost. Hardly annuals can be planted in early spring or in the fall. Examples of hardy annuals are calendula, cornflower (bachelor’s button), larkspur, pansy, and viola. Half-hardy annuals are garden flowers that can tolerate cool weather but may be damaged by frost. In most cases, half-hardy annuals are planted in early spring to produce spring and early summer blooms. Baby’s breath, blue sage, forget-me-nots, snow-on-the-mountain, and torenia are garden flowers that belong to this group of annuals. Garden flowers labeled as tender annuals are sensitive to cold temperatures and may be easily damaged or killed by frost. Because of their low tolerance to the cold, tender annuals may only be planted after the danger of frost has completely passed. Examples of tender annuals are begonia, impatiens, marigold, petunia, and zinnia.

Biennials are garden flowers that take two years or growing seasons to complete their life cycle. Biennials produce only leaves during their first season, then bloom, produce seed, and die in the second season. Because biennials only blossom in one growing season, you need to plant seeds every year, preferably in mid-summer, if you want to have biennial flowers blooming in your garden every season. Examples of biennials are Canterbury bells, foxglove, hollyhock, lupines, and sweet Williams.

Perennials refer to garden flowers that live for several years and often take two or more years to flower. Perennials die back to the ground each fall, then grow again in the spring from underground roots that survived the winter. Compared to annuals, perennials are easier to maintain because they require less watering and fertilizing. Perennials come in a variety of colors, sizes, and bloom periods, thus adding color and interest to your garden year-round. Examples of perennials include asters, daises, daylilies, irises, and violets.