Wisterias are woody deciduous climbers, native to the eastern states of North America, China and Japan. They are cultivated for their showy, pea-like fragrant flowers, which are borne in pendant racemes during spring and summer. The flowers are white, pink and shades of purple-blue, occasionally followed by pendulous green seed pods.
CULTIVATION: Wisterias can be trained to grow against a wall or over arches and pergolas where flowers can hang freely. Wisterias climb by twining around their support. It is only when the stems have reached the top of their support and fall horizontally, that they start flowering. To achieve this in the garden they can be trained to grow along horizontal supports, these need to be 45-60cm (1.5-2ft) apart. Most wisterias are grafted plants and the graft (which you can usually see) should always be above the ground. They are best planted in a well drained, not too fertile soil as too many nutrients will result in all leafy growth and no flowers. A high potash feed will also encourage flowering and can be done in autumn and early spring.
PRUNING: Wisteria should be pruned twice a year.
In July-August: Prune all of the current side-shoot growths back to within 30cm of the main lateral. This should leave 4-6 leaves on each side-shoot. Any side shoot required to extend or train the framework should be left and trained, not pruned!
In January-February: Prune the side shoots back even further leaving only 2 or 3 buds on the side shoot. These will be the lowering spurs on your wisteria.
W. floribunda. This hardy Japanese wisteria has the longest racemes of all the species.
W. sinensis. This Chinese variety, flowers at an early age. It has shorter, fatter racemes than the floribunda.
W. brachybotrys. A Japanese variety with broad racemes which open early in the season, before velvety leaves appear
W. frutescens. A rare American variety which has short racemes from June to August.
It is possible to help identify an unknown plant by noting if the stems twine in a clockwise or anti-clockwise direction when viewed from above. If the stems twine in a clockwise direction the plant is a variety of floribunda. If they twine anti-clockwise it is a cultivar of sinenis, frutescens or brachybotrys. An exception is brachybotrys 'Murasaki Kapitan' which is the only cultivar of this variety to twine in a clockwise direction. If identifying a plant which twines anti-clockwise, frutescens can be identified due to having velvety leaves. Brachybotrys is identifiable by its tendency to flower later in the year with flowers lasting until August.
Every effort has been made to ensure the accuracy of the information given both on our lists and labels. However, some details may vary according to special or geographical circumstances. Varieties offered are subject to availability.