Celery (Apium graveolens) is a cultivated plant, variety in the family Apiaceae, commonly used as a vegetable. Depending on location, either its stalks, or its hypocotyl, are eaten and used in cooking.In North America the dominant variety most commonly available in trade is celery, Apium graveolens var.elery, onions, and bell peppers are the holy trinity of Louisiana Creole and Cajun cuisine. Celery, onions, and carrots make up the French mirepoix, often used as a base for sauces and soups. Celery is a staple in many soups, such as chicken noodle soup.