What are Annuals, Biennials, and Perennials?

The life cycle of a plant can be looked at as having four stages. The plant begins as a seed; goes through the growth process of creating roots, stems, and leaves; flowers; and returns to seed. The classification system of annuals, biennials, and perennials informs you how a particular plant goes through this cycle. Keep in mind, however, that plants interact with their growing environment, and climate may lead them to behave differently than the classification would lead you to expect. Annuals: Annuals are plants that go through a complete life cycle, from seed to seed, in one growing season. Annuals may reseed and grow in the next season, and their reappearance year after year can lead people to mistake annuals for perennials. Popular annuals include cosmos, impatiens, marigolds, petunias, snapdragons, and zinnias. Biennials: Biennials take two years to go through a complete life cycle. The first season's growth only manifests a few, low-lying leaves, and the rest of the cycle takes ... more

The natural lifecycle of a plant begins with a seed. The seed germinates and the plant grows to maturity, producing one or more flowers that develop into fruit. The fruit produces seed that stores the food for the next plant to begin the cycle all over again. An annual goes through its complete cycle in one year. Many vegetables are picked before they reach the final flowering stage, e.g. lettuces. But with others, we eat the final fruit or seeds, e.g. beans, peas, courgettes, pumpkins. A biennial plant is one that takes two years to complete its life cycle. So the seed will be sown in spring or summer, will grow to maturity throughout the year and flower a year later. Biennial vegetables include many cabbage type plants (brassicas), e.g. Brussels sprouts, kale, sprouting broccoli, as well as many root vegetables, e.g. parsnips, carrots, beetroot, salsify. Of course, we usually eat them before they reach the flowering stage. A perennial is one that lives for many years. The seed may be ... more