A plant that completes its life cycle over two growing seasons, producing vegetative growth in the first year and flowers and seeds in the second year.
Biennials fall between an annual and a perennial. After germination, they spend their first growing season developing leaves, roots, and energy reserves rather than producing flowers.
Following a period of winter dormancy, the plant enters its second season and shifts into reproduction. It produces a flower stalk, forms seed, and completes its life cycle. Once seed production is finished, the plant dies.
Many common vegetables are technically biennials, even though gardeners often harvest them during the first year before they ever flower.
Understanding biennials helps gardeners plan for seed saving and long-term harvests. If a biennial is harvested during its first season, you'll never see its flowers or seeds. Gardeners who want to collect seed must allow selected plants to remain in the garden through a second growing season. Knowing when a plant will flower also helps prevent surprise bolting and declining harvests.