"Annual plants are by definition plants whose life cycle lasts only one year, from seed to blooms to seed...Perennials, like old friends, return year after year, growing in size and stature until they reach their full maturity. Although they live on longer, many perennials lose their vigor after 3-4 years, and should be replaced. Most perennial plants can be divided to produce new plants, or they can be grown from seeds or cuttings."