If you knew how awful it is, you would have nothing to do with oriental bittersweet! It is an aggressive, woody, deciduous, perennial vine capable of girdling stems and trunks of shrubs and trees, damaging their bark and underlying tissue. Despite its weedy behavior, oriental bittersweet is still sold and planted as an ornamental vine and should be avoided.
- Leaves: Finely toothed, round glossy leaves are arranged alternately on the vine. They range from 2 to 5 inches long and 1.5 to 2 inches wide.
- Flowers: Clusters of 2 to 7 blossoms where the leaf attaches to the stem (leaf axil). Each flower has 5 petals and 5 sepals.
- Fruit: Green-to-yellow round fruits ripen in the fall. Upon ripening, the fruits split open revealing three red-orange, fleshy berries that remain on the vine through the winter. The many birds and small mammals that feed on the berries distribute seed far and wide. A single plant can produce almost 400 fruits!
- Distribution: Oriental bittersweet’s distribution ranges from central Maine south to North Carolina and west to Illinois;
- Ecology: It can grow in woodlands, fields, hedgerows, coastal areas, and salt marsh edges. It tolerates shade but prefers full sun.
- Mechanical control: Pull light infestations by hand—before fruiting, if possible. If fruits are present, bag the vines to make sure the seeds do not contaminate the site. Cutting the vines at the base early in the season will prevent flowering and fruiting, but you must remove all of the roots so the bittersweet will not re-sprout. Frequent mowing will also exclude oriental bittersweet, but infrequent mowing—two to three times a year—can stimulate root suckering.
- Chemical control: You can successfully manage heavy infestations of non-native bittersweet with herbicides containing the active ingredient Triclopyr. The chemical is most effective applied immediately to the cut stem surface of cut or mowed vines. Apply herbicides prior to the emergence of native plants or after the last killing frost to help avoid herbicide contact with desirable plants. As with any herbicide, carefully follow the label guidelines when handling and applying.
American bittersweet (Celastrus scandens) is native to the eastern United States and is easily confused with oriental bittersweet. Leaf shape is highly variable and not a good characteristic for identifying American vs. Oriental bittersweet. Watch for flowers and fruits to distinguish the two:
- American bittersweet flowers and fruits are only found at the ends of stems, Oriental bittersweet flowers and fruits are found all along the stem at leaf axils.
- American bittersweet has orange capsules around red fruits, Oriental bittersweet has yellow capsules around red fruits.
A HOLIDAY CAUTION: Do NOT use oriental bittersweet in outdoor decorations! If you have any decorations containing oriental bittersweet fruits, be sure to bag them and discard—Do not compost!
Article by Bob Wardwell, Extension Master GardenerSM Volunteer
For More Information:
- Identifying Oriental and American Bittersweet: USGS bittersweet identification fact sheet
- Celastrus orbiculatus: https://plants.ces.ncsu.edu/plants/all/celastrus-orbiculatus/
- American (climbing) bittersweet (Celastrus scandens) and its cultivars https://webapps8.dnr.state.mn.us/restoreyourshore/plants/plant details/114
- Backyard Bullies: https://www.buncombemastergardener.org/illicit-harvest/