With insignificant flowers that develop into clusters of yellowish-orange capsules, which then separate to reveal bright orange-red berries, American bittersweet (Celastrus scandens) and Oriental bittersweet (C. rosthornianus) are vigorously growing perennial vines. The American variety is slightly less vigorous than the Oriental variety, but it produces larger and more prominent berries in autumn. The berries stay on the vines well into winter, although the Oriental bittersweet often dies down to its roots in colder northern areas.
Siting and Culture
Bittersweet must be grown in full sun in order to produce its desirable berries. It grows well in all types of soil, but it must be well-drained. Do not plant bittersweet near trees. The vigorous growing habit of bittersweet can kill a tree by tightly girdling its trunk or branches. Instead, train bittersweet to climb a tall fence or trellis. They prefer average soil and are not bothered with pests or diseases, except for euonymus scale.
Plant Both Male and Female Plants
A dioecious vine, both male and female vines must be planted for the females to produce fruit. Plant one male to pollinate every five or six females. There is no way to tell the plant's sex until berries appear; cultivation from established vines whose sex is known is the best way to ensure that you have both male and female plants.
Regular pruning to contain their size is the most care that bittersweet vines require. Because the male vines grow more vigorously than the female vines, hard prune them regularly so they do not overwhelm the females and crowd them out. Prune females to contain their size and to remove any dead or diseased branches. Pruning is best done in late winter or very early spring.