Biennial

dill

biennial, any herbaceous flowering plant that completes its life cycle in two growing seasons. During the first growing season, biennials produce roots, stems, and leaves. During the second growing season, they produce flowers, fruits, and seeds, and then they die. Biennial plants are typically native to temperate climates and frequently overwinter underground. See also annual; perennial.

Many members of the parsley family (Apiaceae) have a biennial life cycle, including parsley, coriander, dill, and Queen Anne’s lace. One of the most economically important biennials is the carrot, which is harvested after a single growing season when the food storage organ (the edible root) has achieved its greatest size. If left to go to seed, the food stored in the taproot will be used by the plant to fuel the growth of its reproductive structures during the second growing season. Certain bellflowers and some forget-me-nots also live for only two growing seasons.