Annuals, perennials, perennials, annuals--the nomenclature with this way of classifying flowers has always struck me as backward, even when I was eight years old. Annuals should be flowers you plant once and have done with it. Perennials should be those you must plant every year. So I thought. It's a lost battle.

Horticulturalists designate by the lifespan of the flower, not how often they're planted. Annuals complete their cycle in a 12-month period. Perennials last as many as 36 months. Regardless of such quibbles, whether you buy small beds of pansies or sweet peas in April, or plant from seed in October or February, annuals are a delight. We tend to think of them, perhaps, in more formal settings, on an 18th century house and garden pilgrimage to the Eastern Shore of Maryland, for example, or in a side yard in Colonial Williamsburg.

But annuals are more adaptable than that. You're limited primarily by your imagination, though soil and sun considerations are obviously critical. Imagine a bed of evening primrose or impatiens in the semi-shade, backed by dwarf boxwood or palm sedge grass, or a succession of calliopsis and sweet alyssum blooms in full or dappled sun throughout the summer.

Different Annuals, Different Roles

Let's look at the edging annuals, for a start, and work backwards. Ideally border plants will have a dense base and resist weeds. Dwarf ageratum is a good example. It grows four to six inches tall, grows well in full and partial sun, and features dense clusters of vibrant blue flowers.

Whether your garden runs front to back against a fence or wall, or forms an island amidst other landscape features, you'll be looking for taller flowers as well, of course. Mirabilis, also known as four o'clock and marvel of Peru, grows about two feet tall. It does especially well as a temporary hedge or flowerbed backdrop, bearing hundreds of blooms throughout the season in a variety of colors.