This genus includes about ten species of deciduous climbers, vigorous, twining, originating from the damp woodlands and watercourses of Asia (China, Japan, Korea) and the central and southern United States. They have pinnate leaves up to 35cm long, made up of ovate-lanceolate leaflets, almost always dark green. Grown chiefly for their extremely beautiful and showy drooping racemes of scented, butterfly-like flowers, that blossom in late spring and again in summer, though less obviously, as they have to emerge from the foliage that has meantime grown up. Flowers are succeeded by fruits like long pods, containing the seeds (poisonous). They adapt to all terrain, except if too hardpacked or stagnant and are used to decorate walls, fences, pergolas, trunks – even very high ones – of old trees, etc. Can be grown as trees with single trunk, with rather disorderly crown, but truly spectacular.