Wisteria brachybotrys 'Shiro-kapitan'

Wisteria brachybotrys 'Shiro-kapitan'

The oak pergola forms a wonderfully dramatic entrance to the Hilltop Garden at RHS Garden Hyde Hall and its chunky rustic pillars and beams are clothed in Wisteria brachybotrys 'Shiro-kapitan'. Although this wisteria usually flowers in mid-April, this year it is a little later due to the colder winter.

Vital statistics

Common name

White silky wisteria

Family

Papilionaceae

Height & spread

9m (28ft) and more

Form

Deciduous climber

Soil

Fertile, moist but well-drained soil

Aspect

Full sun

Hardiness

Fully hardy

Wisteria

This is a genus of about six species of twining, woody and deciduous climbers. They grow in moist woodland and on stream banks in the USA, China, Korea and Japan.

They are cultivated for their showy, fragrant flowers which are borne in spring or summer. The individual pea-like flowers develop in long pendent racemes that have been known to reach up to 1.8m (6ft) in selected forms of Wisteria floribunda. The flowers are followed by bean-like, green seed pods in autumn. They have dark green alternate, pinnate leaves, 35cm (14in) long.

Wisteria was named for Caspar Wistar (1761-1818), professor of anatomy at the University of Pennsylvania whose main interests, outside of medicine, were palaeontology and botany. He was one of the early owners of what is now Vernon Park, Philadelphia which is noted for its fine collection of rare trees and shrubs.

Wisteria brachybotrys 'Shiro-kapitan'

Wisteria brachybotrys is a twining climber with pinnate, softly hairy leaves to 35cm (14in) long, each composed of 9-13 ovate to lance-shaped leaflets. Pea-like, fragrant, yellow-marked, violet to white flowers are produced in racemes, to 15cm (6in) long in early summer. They are followed by bean-like, velvety green seed pods, to 20cm (8in). Brachybotrys is Latin meaning short-clustered in respect of the length of the racemes.

Wisteria brachybotrys 'Shiro-kapitan' is a cultivar that produces white flowers with a yellow stain at the base of each standard. Occasionally it may produce double flowers.

Cultivation

• Grow in any fertile, moist, well-drained soil in full sun or partial shade, though they will flower more profusely in full sun. Traditionally wisterias are trained against walls, fences and pergolas but they can also be grown through large deciduous trees.
• Given good soil conditions wisterias can establish rapidly but will need training to produce the best flowering display in a limited space, though specimens can be left to naturally grow through large trees where space is less limiting.
• Prune initially to form a suitable framework. Once established prune to encourage the formation of flowering spurs, close to the main framework of the plant.
• Wisterias can be affected by several pests and diseases including leaf spot, aphids, brown scale and honey fungus.

Propagation

• Propagate using basal cuttings from sideshoots in early to midsummer; encourage rooting by providing bottom heat. Cuttings can take up to nine years to flower. 
• Alternatively, propagate by layering in the spring. Lay any convenient long shoot along the ground and cover it with a shallow layer of soil. The shoot will readily produce roots at intervals along the stem. 
• When these are well formed, the shoot can be divided up into a number of plants. These should be potted up and kept in a lightly shaded position in a greenhouse until well established and can then be planted out. 
• Plants can be raised from seed but are very variable, can take up to 20 years to bear flowers, and are usually inferior to named cultivars. Sow seeds in spring at 10-13ºC (50-55ºF) after soaking in hot water for about 18 hours. Take care as the seeds are poisonous.