Asiatic Bittersweet (Celastrus orbiculatus)

Key Identification Features

• Vine

• Alternate leaf arrangement, with glossy, toothed round leaves

• Greenish/white flowers at leaf axils

Description

Asiatic bittersweet is a deciduous woody vine that climbs trees and shrubs and creates thick sprawling masses. If no host plants are available to climb it will twine several vines together to create a rigid growth structure until a host can be reached. It can grow to lengths of 60 feet, and the stems of mature plants can reach 4 inches in diameter. Its leaves are alternate, glossy and rounded with slightly toothed margins. In late spring it blooms clusters of small greenish-white flowers, followed by green and yellow fruit that when ripe split to reveal scarlet berries that persist into winter. It is easily confused with the native American bittersweet (Celastrus scandens), which it often hybridizes with. American bittersweet produces flowers at stem tips, while Asiatic bittersweet flowers from its leaf axils.

Native Range

Asiatic bittersweet is native to Eastern Asia, Korea, China and Japan. It was first introduced into the United States in the 1860s as an ornamental. It is still frequently sold for landscaping purposes, despite the bans placed on it in many states due to its invasive qualities.

Habitat and Dispersion

Asiatic bittersweet is a generalist that is found in a variety of habitats such as fields, hedgerows, wetland margins, forest edges and open woodlands. Although it does best in open sunny areas, it is shade tolerant which allows it to invade forests. It is an aggressive vine that uses other plants as scaffolding, and creates dense tangled swaths that shade out and smother other plants. It can do substantial damage to trees by girdling and weighing down limbs, which can result in their eventual death. It is spread primarily through the dispersal of its seeds by birds which feed on its berries. It expands locally by its rapid vegetative growth.

Best Management Practices

Smaller infestations of Asiatic bittersweet can be successfully controlled by mechanical means. Vines should be cut, pulled, dug up and removed as much as possible. This strategy becomes more difficult once the vines are larger in size and have reached higher levels of the canopy. Cutting the vines and treating cut stumps with herbicide has proven effective. Care should be taken to confirm the plant being targeted is indeed invasive Asiatic bittersweet, and not the native and beneficial American bittersweet.

Additional Resources

USDA

University of CT