Common Name: Oriental Bittersweet
Scientific Name: Celastrus orbiculatus Thunb.
Alternate Names: Asian bittersweet, climbing spindleberry
Related Species: C. scandens (native)
Legal Status: Prohibited - Eradicate
All above and below ground parts of the plant must be destroyed. Additionally, no transportation, propagation, or sale of this plant is allowed. Failure to comply may result in an enforcement action by the county or local municipality. Minnesota Noxious Weed Law.
Oriental bittersweet is a woody vine that is native to China, Korea, and Japan. It was introduced to North America in the mid-1860s as an ornamental. Oriental bittersweet has since spread throughout the temperate eastern US and Canada. The first confirmed Oriental bittersweet infestations in Minnesota were found, reported, and controlled in 2010 by the Minnesota Department of Transportation on their rights-of-way in the Twin Cities area. Tracing back these infestations, we learned that they were planted along fences by persons who thought they had planted American bittersweet. A large infestation of Oriental bittersweet has been confirmed in Winona, Minnesota.
- The vines girdle and smother trees and shrubs.
- Deciduous vine that grows up to 66' long. The vines climb by winding around a tree or other support structure. There are whitish, raised lenticels on the vine.
- The leaves are green then turn yellow in the fall. They are alternate and vary in shape from oblong to almost round. Leaf size is also variable from 2- 5" long to 1.4- 2" wide. The leaf margins have rounded teeth.
- There are separate male and female plants. Flowering occurs in the spring and flowers are arranged in clusters of 2- 7 at the leaf axils. Each flower has 5 petals and 5 sepals.
- Fruits are round and change in color from green to bright red with a yellow capsule as they mature. Typical female plants can produce up to 370 fruits which ripen in the fall.
- Information on differentiating Oriental and American bittersweet species
Oriental bittersweet is found in forested areas, field and forest margins, meadows, rights-of-way, fence rows, along waterways and in residential landscapes. This plant thrives in a range of soil types and light levels from full sun to shade.
Means of spread and distribution
Oriental bittersweet reproduces by seeds and rhizomes. The fruits are consumed, then dispersed by birds and mammals; ingested seeds have a higher germination rate than seeds that fall to the ground. People can move seed by using fruiting stems in flower arrangements. Oriental bittersweet is sometimes mistakenly labeled and sold by nurseries and in garden centers as American bittersweet.
Oriental bittersweet vines twine around trees and other supports resulting in girdled and smothered trees and shrubs. Entire plant communities may be overwhelmed by Oriental bittersweet. In addition, the added weight of the vines covered with snow and ice can break trees and shrubs. Oriental bittersweet outcompetes and displaces our indigenous American bittersweet to the point that Connecticut now lists the formerly common American bittersweet as a species of concern.
Prevention and management
- Avoid spreading Oriental bittersweet by learning to recognize it and not planting it. Do not collect or use the fruiting stems for ornamental purposes. Remove all infestations from your property. Bag or burn all fruit for disposal.
- For all management options, infested sites will need to be monitored and treated repeatedly until the seedbanks are depleted.
- Foliar or cut stump herbicide applications can be effective. For specific herbicide recommendations, check with your local University of Minnesota Extension personnel, co-op, or certified landscape care expert. There are several businesses throughout the state with certified herbicide applicators that can be hired to perform chemical applications.
- Regular, weekly mowing will control Oriental bittersweet, but less frequent mowing may result in suckering from the roots.