Annual plants live for only one growing season, during which they produce seeds and then die. Familiar annual plants include impatiens, zinnias, and sunflowers. Biennial plants, such as some types of foxglove, live for two growing seasons before setting seed and dying. Then, when the season's over and the plants die, you pull them out. Next spring, the cycle begins anew.
Perennial plants remain in the ground year after year.
Once established, most perennials need minimal upkeep in the form of watering and fertilizing, since their roots are more far-ranging than those of annual plants. Many perennials spread readily, filling out garden spaces and providing more and more color each year. Most perennial plants have a distinct bloom period, lasting anywhere from a week to a month or more. A few will describe certain plants as continuous bloomers, but even these usually have a period of peak bloom. At first, this may seem like a drawback, since each plant won't flower all summer.