This section is from the book "Commercial Gardening Vol4", by John Weathers (the Editor). Also available from Amazon: Commercial Gardening, A Practical & Scientific Treatise For Market Gardeners.
The best-known species is W. chinensis, a rampant deciduous woody climber, with pinnate leaves and drooping racemes of pale-purple Pea-like flowers in early summer. There is a white-flowered variety, alba; a larger-flowered one, macrobotrys; one with silver and green foliage, variegata; and a double-flowered one, flore pleno. W. multijuga, from Japan, has lilac-coloured flowers in racemes often over 2 ft. long. Other species are brachybotrys, a Japanese, shrub 3-5 ft. high, with violet-purple flowers in short racemes; frutescens, from North America, with deep-blue flowers, much better in the variety magnified; and japonica, a shrubby species with white flowers. The greatest trade is done in W. chinensis and W. multijuga, which are raised by grafting pieces of dormant stem in pieces of root plunged in bottom heat. (See Vol. I, p. 88).