Annuals vs. Perennials: An Inter-Shrub Showdown

How long do you want your new plants to stick around? Check out Groupon's guide to annuals and perennials to help you pick the right flowers for your garden.

Almost all plants fall into one of two categories according to the duration of their life cycle. Annuals, which include petunias, marigolds, and impatiens, last only a single growing season, so they must be replanted each year. On the other hand, perennials such as peonies and hostas can withstand frost and other hazards of colder weather and survive for three years or more. To help choose between the two, gardeners can ask themselves these basic questions:

How much work do I want to do?

If planted properly, the hardy perennials mostly will take care of themselves, though you may need to divide the plants every few years to prevent overcrowding. By contrast, the high-maintenance annuals need regular watering, fertilizing, deadheading, and other types of care to maintain their brilliant blooms and feed their oversize egos.

How soon do I want results?

Annuals are highly sensitive to frost—plant them too early in the season, and they might be killed off by the winter's last cold snap. But once planted, their large, vibrantly colored flowers usually will bloom immediately and last the entire season. Conversely, perennials may be thick-stemmed enough to withstand the winter's final frosts, but many won't bloom until their second year, and even then only for a few weeks.

What's my hardiness zone?

Perennials don't live out their whole lifespan in every climate. A plant that thrives for three or more years in its native subtropics may succumb to the first frost in the northern latitudes. Before you invest in a perennial plant, check whether or not it should be treated as an annual in your climate. Often, it helps to know your local hardiness zone—a US Department of Agriculture standard based on a region's average temperature—before making a decision.

Do I want foliage that will last through winter?

Herbaceous perennials such as peonies and hostas will lose everything but their roots in the winter, then regrow them in the spring, but woody perennials such as azaleas—protected by hard, stiff stems filled with down feathers—will stick it out through the colder months.

What about biennials?

As with any classification system, the duality of the annual-perennial split isn't quite accurate. Some plants such as foxglove and black-eyed susans are actually biennials—that is, they have a two-year life cycle that places them roughly between the two categories. Still, you can use that to your advantage, since planting a new batch of biennials every year can ensure that at least half of the plants are always in flower.