biennial, plant requiring two years to complete its life cycle, as distinguished from an annual or a perennial. In the first year a biennial usually produces a rosette of leaves (e.g., the cabbage) and a fleshy root, which acts as a food reserve over the winter. During the second year the plant produces flowers and seeds and, having exhausted its food reserve, then dies. Short-lived perennials (e.g., the hollyhock) are often treated as biennials. Some biennials will, like annuals, bloom in the same season if sown early; others reseed themselves or produce offsets, thus perpetuating the plant indefinitely so that it becomes essentially a perennial. There are very few true biennials. Many are crop plants, such as carrots and parsnips, which are harvested for their succulent roots at the end of their first growing season.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.