About 140 species of annuals and perennials from the northern temperate zone and South America. They are largely climbers, clinging by leaf-tip tendrils, though some species are self-supporting. The leaves are usually pinnate and the pea-shaped flowers are borne either in stalked racemes or small clusters (or solitarily) direct from the leaf axils. The typical legume seed pod explodes when ripe.
A few of the smaller non-climbing species are suitable for the larger rock garden or alpine house. Ordinary soil and a moderately sunny site are all that is required, most species also tolerate some shade. Propagation by division in late winter or autumn, or seed in spring. Basal cuttings could also be tried in late spring or early summer.