Apium

A cool-season root vegetable in the carrot family (Apiaceae) grown for its swollen, edible, brown, turnip-like root, which tastes like celery with an additional turnip-like flavoring. Biennial by nature, it is grown as an annual: in its first season it forms a basal rosette of aromatic, pinnately divided leaves above the enlarging root, and only in a second year would it send up a summer bloom of off-white flowers in umbels. Missouri Botanical Garden PlantFinder describes a plant 2 to 3 feet tall and 12 to 18 inches wide that wants full sun, rich moist well-drained soil, and consistent water. It dislikes summer heat and humidity, growing best between 60 to 75°F, and the root is ready to harvest after 3-4 months.

A cool-season biennial vegetable in the carrot family (Apiaceae), grown as an annual for its crisp, edible ribbed leaf stalks. Apium graveolens is native to temperate Mediterranean Europe, Asia, and Africa - not North America. It demands rich, consistently moist soil and steady cool temperatures (60 to 75°F); heat and drought turn the stalks stringy and bitter, which is why it is one of the more finicky garden vegetables.