Bittersweets CAN be tamed! They are extremely vigorous, healthy and have splendid yellow leaves in autumn, and are often used for high greening, as there is less pruning to be done as with a Wisteria. In the garden, they can green up a pergola. The fruit will feed birds in winter.
Celastrus orbiculatus / Bittersweet
Sunny (full sun) to semi-shaded position, may be grown in the shade, but will produce less flowers and fruit. Best in nutrient rich soil. Distance between plants: 1.5 to 4 meters.
Vigorous twiners with sturdy stem formation. Celastrus orbiculatus from China is the more common variety. It has a strong growth, 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 as well as the Mini-Kiwi. Foliage from May to October, yellow autumn colouring. 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. There should be some yearly pruning to get on top of the very fast growth, especially in the first 6 to 12 years.
The growth support should be sturdy, old trees can also be colonised by a celastrus. Lightning conductors, downpipes and roof gutters etc. should not be reached by the shoots and any growth supports 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 below) are suitable if the ropes are arranged parallel to each other as for the Wisteria: the shoots should be be twining around the wires and strangle them. Heavy or Massive Growth Support Systems.