This Plant Profile features Wisteria sinensis and its close relatives. W. sinensis is undoubtedly one of the most spectacular climbing plants found growing in gardens in temperate climates around the globe.
A genus of about ten or so species that includes W. sinensis (Chinese wisteria), W. floribunda (Japanese wisteria) and W. brachybotrys (Silky wisteria), Wisterias are found growing naturally in Asia and parts of the USA. The garden varieties and hybrids are derived largely from Asian Wisterias from China and Japan.
The Wisterias are vigorous growing, twining, woody climbers with large, compound, deciduous leaves and belong to the legume or bean family. In spring the plants are smothered with racemes of pea-like fragrant flowers that are borne simultaneously with the new spring foliage. The flowers hang down from the tough, woody stems like large bunches of grapes and are best appreciated when the Wisteria is growing over a pergola. The flowers last for a few weeks and are followed by large bean-like seedpods. All parts of the plants can cause discomfort if ingested or swallowed due to the presence of a poisonous lectin called wistarin.
Wisterias can be trained to cover pergolas, grow along sturdy fences, climb large trees and spread over archways or they can simply grow propped up against large building or boundary walls. With regular pruning they can also be manipulated into trees or standards with a single stem and a rounded crown. This does require careful and calculated care and attention to ensure that the flowering spurs are not removed at pruning time. The climbing versions are best pruned in winter or after flowering, with light pruning through the summer season to keep the vigorous growth in check.
Wisterias grow best in cold, temperate climates with winter frosts and snow and are not suitable for sub-tropical climates. If winter temperatures are not cold enough the plants grow vigorously but do not produce flowers, invariably disappointing the gardener. They flourish in rich, loamy soils and perform best in full sun. Regular watering and feeding through the growing season will ensure an abundance of spring flowers.
A large Wisteria in full bloom in spring just has to be one of the finest floral spectacles imaginable. Many world-renowned gardens in England, Europe and North America have them flourishing in prominent positions for just this spring grandeur. If you are blessed with the climate and the space in your garden then this spring would be a great time to become entangled with a Wisteria.
Here in South Africa various named hybrids and cultivars are available from select nurseries and garden centres and include Wisterias that flower in pink, white, lavender, lilac-blue and violet shades.
Article by Gerald Schofield