a plant having a life cycle that normally takes two seasons from germination to death
Many biennials reseed themselves.
—for the nobler plants are valued for the fruit they bear at last in the air and light, far from the ground, and are not treated like the humbler esculents, which, though they may be biennials, are cultivated only till they have perfected their root, and often cut down at top for this purpose, so that most would not know them in their flowering season.
Henry David Thoreau -- Walden
All through the house there were seed packets and Xeroxed pictures of perennials and biennials and alpines and annuals and roses in every color you could imagine.
Sarah Dessen -- That Summer
parsnips and carrots are biennial plants often grown as annuals