Synonyms: Wistaria
Family: Papilionaceae

There are ten species or so in this genus of deciduous climbers, which have twining stems, soft, light green, much-divided leaves, and trusses of delicate, pea-shaped flowers. Sometimes fragrant, flowers may be shades of blue, mauve, pink and white, and are followed by bean-like fruit. Wisteria is a garden favourite in a range of climates, providing summer shade and an attractive display in late spring and early summer. It is native to China, Japan, Korea and central and southern United States.

Species

W. brachybotrys, from Japan, is known as silky wisteria or Yama Fuji. It has short, broad trusses of delightfully scented flowers that are deep violet, marked in yellow and white. Two outstanding cultivars are 'Shiro Kapitan', with large, white, fragrant flowers, and 'Murasaki Kapitan', which produces dark blue flowers, conspicuously marked with white. The flowers have little scent.

W. floribunda, Japanese wis­teria, has long sterns, 10 m (33 ft) or more in length. The trusses of fragrant flowers can grow up to 1 m (3 ft) long, but are usually about half this size. They may be blueish violet, pink or white. The velvety fruit is about 15 cm (6 in) long. Cultivar 'Alba' or 'Shiro Noda' bears white flowers; 'Carnea' or 'Kuchibeni' has palest pink flowers; 'Macrobotrys' has very long trusses of mauve-blue flowers; 'Rosea' or 'Honbeni', rose wisteria, has rose pink flowers; and 'Violacea Plena' bears double, violet-blue flowers.

W. frutescens, a native of eastern and central North America, has trusses of lilac or purple flowers, followed by 10 cm (4 in) long fruit.

W. japonica, from Japan and Korea, has 30 cm (12 in) long trusses of greenish white flowers, sometimes borne in pairs, followed by smooth fruits.

W. macrostachya, Kentucky wisteria, from swampy areas of central North America, bears trusses of lilac or blue flowers, about 30 cm (12 in) long, followed by 12 cm (5 in) long fruit.

W. sinensis, Chinese wisteria, is a very vigorous plant, sometimes growing to 10 m (33 ft) or more high. The trusses of mauve-blue flowers are 30 cm (12 in) long and appear before the leaves in spring. The flowers have only a light fragrance. Cultivar 'Alba' has very fragrant, white flowers.

Cultivation

Wisteria can be grown in almost any soil, provided it is well drained. However, it does need full sun, protection from wind and a strong support. Established wisterias need regu­lar pruning to prevent congested growth. Train a permanent framework of stems to the shape desired, then spur prune to this. In midsum­mer, cut hack the new, lateral shoots to within five or six buds of the main framework. Then, in midwinter, prune the plants back further, to within two or three buds of the framework. Wisterias can also be trained as standards. Propagation is by layering in spring.

Climate

Zone 5 for most, but zone 8 for W. japonica, zone 6 for W. macrostachya.