Wisteria sinensis // floribunda // frutescens
The Wisterias are popular for their abundance of flowers and vigorous growth habit. Wisteria has been known for centuries in the Asian art of gardens. Ideal for high greening. There are several hybrid forms which cannot be identified according to the direction of their twining etc, hence an exact species identification based on eg the twining (right or left) of available Wisterias is almost impossible. A poisonous plant. Inadequate espalier planning and maintenance can cause considerable building damages.
Position in full sun is best, areas with no direct sun but a high light density (eg courtyards) or semi-shade are possible, but plants will produce less flowers. Distance from plant to plant: 3 - 8 m.
An extremely strong and vigorous twiner, which can reach 20m height, a “Green Octopus” - the young strangling arms reaching an action radius of more than 1m. Light-shunning growth, into nooks and crannies etc, with blast-effect. Feathery leaves, mostly light green, sometimes with an orange-brown tinge. Foliage from May to November, rarely with yellow autumn colouring.
Flower and Fruit
Blue, white and pink varieties, in two main groups: Wisteria sinensis (Chinese Wisteria) and Wisteria floribunda (Japanese Wisteria). W. sinensis flowers at the beginning of May, mostly before the shoots appear, followed in midsummer by some sparse flowers. W. floribunda flowers a little later. Another species, Wisteria frutescens (American Wisteria), develops flowers at an earlier age, but is frost tender. Opening flower buds deep blue and deep purple, fully open flowers soon fading to a grey-blue. Flowers often simultaneously with lilac. Fruit are long hairy pods. Non-grafted specimens often develop flowers after many years only, and in some cases bear but a few flowers.
Summer and winter pruning as illustrated in photos. Regular pruning is absolutely essential to prevent damage to support systems.
Sturdy, preferably rod-like support systems, designed for anticipaded height and width of plant. A simple linear system rather than covering large areas, no timber trellises. Wire ropes are suitable if the main stem is guided strongly parallel to the wires, without twining, as illustrated in the photos. The short side branches are to be arranged so that any scratching of the wall render is prevented should windy conditions make the newel and hence the plant turn around. Lightning conductors, downpipes and eave gutters etc are not to be reached by the plant, all growth supports should have a distance of 2 metres from any such building elements and to the eave gutters, to the sides as well as from the top. For suitable rope systems see below, use Heavy or Massive systems, in case of pot plants Easy or Medium systems will be adequate.