Catnip grows to a height of three or four feet and has featherlike, light green foliage and small clusters of lavender flowers that grow on spikes. A member of the mint family, catnip is also used in food and herbal remedies. For example, tea made from the leaves and flowers of Nepeta cataria is said to relieve coughs. The oil extracted from catnip plants is even used in natural mosquito repellents. If you're planning to grow catnip, for your cat or yourself, keep in mind that there are different types of catnip and that all common types are invasive.