What are the differences between annuals, perennials, and biennials?

Annuals: Blooms the first year from seed and then dies at the end of its bloom cycle. Will often, but not reliably "re-seed" and bloom again the following - and subsequent - years. Perennials: Establishes a root system in year one, and blooms the following year. If established amidst suitable conditions, perennials will typically provide several years of abundant growth. Biennials: A tricky and unpredictable sort, a biennial grows leaves during its first season, blooms it's second, and then generally dies. Depending on climactic conditions, however, will sometimes behave as either an annual or perennial.  more