Crassula is a very large genus containing over 300 species of succulent plants from southern Africa, Madagascar, Australia, Asia and Europe.  They can be annual, biannual, or perennial, and many grow as spreading plants or shrubs with woody stems.  Dry tolerant, they are suited to arid gardens, rockeries or containers,  and make an attractive feature plant or ground cover.  They generally prefer full sun or part shade conditions with well-draining soil, and should be watered reasonably regularly when growing and flowering, and kept drier at other times. They can also be kept indoors in a well-lit position.  Crassulas have very attractive leaf-form and shape and are a lovely addition to the garden all year round.