ORIGIN: Wisteria are deciduous climbers found originally on the banks of streams and in moist woodlands in China, Japan and Korea and central and southern USA where they achieve heights of ten metres or more.
Wisterias do not normally conform to the styling of bonsai. They are styled to show off their racemes of flowers. There are various varieties which allows colour changes these can consist of either purple, white or blue. The season for flowering takes place in late spring or summer. The two species most suitable for bonsai are W. floribunda (Japanese Wisteria and W. chinensis) Chinese Wisteria.
Flowering: Wisteria will not flower until they reach a certain age, this is usually around ten years. Wisteria should be pruned to encourage flowering. Prune back all shoots that are not needed to form the structure of the tree, leave 4 to 6 inches on each shoot. This should be done after flowering, you may have to repeat this 2 or 3 times until Autumn. During mid-winter reduce these spurs again to 3-4 inches leaving only 2-3 buds.
These repeated prunings followed by a hard prune in mid-winter not only control the vigour but encourage flower production at the expense of leaf growth, this also encourages compact flowering and foliage. To maximize flowering repoting should be carried out in early spring just after flowering has finished this will allow the tree to shute hard on vegetative growth.
Fertilizing: As Wisteria are great at storing nitrogen, feeding needs to consist of a low nitrogen content, this will also contribute to better and denser flowering. Feed fortnightly after flowering has finished until autumn.
Watering: Wisteria require large amounts of water as they need to be kept continually moist similar to the requirements of grape vines these are also excellent specimens for bonsai. Make sure that you have a good free draining soil mix because wisteria are susceptible to root rot.
Repotting: This needs to be carried out every 2 to 3 years after flowering is finished. However if repotted in early spring your flowering production will be reduced. For the soil mix I have had great success using 1 part Debco bonsai mix to 1 part Akadama, if however you can�t obtain Akadama you can use course cut river sand, you can obtain this from a cement supplier such as Boral or Readymix as the sand is really washed well and there is no rubbish left in the mix.
Pests: Aphids, brown scale and leafspot are usually the main problems.
Styles most suited: Wisteria are styled into forms that allow their flowers to cascade to their full length. These styles can be informal upright, slanting or semi-cascade or full cascade.
"Bonsai is the creation of living art and the blending of elements"