Bittersweets CAN be tamed! They are extremely vigorous, healthy, have splendid yellow leaves in autumn, and are often used for high greening, as there is less pruning to be done than with wisteria. In the garden they can green up a pergola. The fruit will feed birds in winter.
Celastrus orbiculatus / Bittersweet
Bittersweet needs a sunny (full sun) to semi-shaded position; it can be grown in the shade, but will produce fewer flowers and fruit. Best in nutrient-rich soil. Distance between plants: 1.5 - 4 metres.
These are vigorous twiners with sturdy stem formation. Celastrus orbiculatus from China is the more common variety. It has a strong growth with broad oval, dentate or serrate, and clearly acuminate leaves. Celastrus scandens from North America has oval, acuminate leaves with undulating margins. There are several other varieties that resemble each other and the mini-kiwi. Foliage from May to October, yellow autumn colouring. Has inconspicuous, pale-green flowers, mostly dioecious (male and female on separate plants). In order to get the decorative berries, it is best to plant several specimens together. Prune once a year to handle its very fast growth, especially in the first 6 - 12 years.
The climbing support should be sturdy... even old trees will do the trick. Lightning conductors, downpipes, roof gutters, etc.. should not be reached by the shoots, and any trellis supports (brackets/mounts) should have a distance of at least 1.5 m from all such structures and to the roof gutters-- to the side as well as to the top. Wire rope systems (see chart at the bottom) are suitable if the ropes are arranged parallel to each other as they are with wisteria: the shoots must therefore not be wrapped around the cable for long... if it 'chokes' the rope, the anchor screws may be torn off from the wall with the deformation of the cable. Choose a heavy or massive trellis system.