Also known as: Asian bittersweet
Origin: Oriental bittersweet was introduced to the United States from Asia in the 1860s as an ornamental vine. Its showy, berried vines are traditionally collected in winter for home decorations. It is still widely planted as an ornamental, contributing to its spread.
Description: Oriental bittersweet is a climbing, twining, woody vine with alternate, bluntly-toothed, elliptic-to-rounded, glossy leaves about 1-5 inches long. There are separate male and female plants. In spring, female plants produce clusters of tiny, greenish flowers which are followed, in summer, by capsules which change from green to yellow-orange to tan. These capsules split in winter to reveal fleshy, red, 3-sectioned fruits.
Correct identification of this species is very important because of its close resemblance to American bittersweet, which it is displacing. American bittersweet tends to have leaves which are about twice as long as they are wide, whereas the leaves of Oriental bittersweet tend to be nearly as wide as they are long. Additionally, the flower clusters and fruits of American bittersweet occur only at the ends of the stems rather than along its length. Unfortunately, hybridization between the 2 species occurs, potentially leading to a loss of genetic identity of the native plant.
Habitat description: This perennial vine prefers full to partial sun. This vine invades disturbed young forests and abandoned old fields. It is easily recognizable as "a" Bittersweet vine by its bright orange fruits in the Fall and Winter. Oriental Bittersweet can be found along fence rows. There is a very large population of bittersweet on Helmsburg Road, just south of Morrison Road. It is in a cleared area next to a driveway on the west side of Helmsburg Road.
Distribution: This vine is found along roadsides, in forest openings, along forest edges, in fields, and at old home sites. It is somewhat shade-tolerant, allowing it also to grow in open forests.
Problem: Oriental bittersweet can grow to completely cover other vegetation, shading out even large trees or causing them to break or blow over due to its excessive weight. It can also kill trees by girdling. It fruits profusely, and its seeds are spread rapidly by birds and other animals.
Control: Hand-pulling of seedlings or small plants may be effective, but care should be taken not to disturb the soil more than necessary. Glyphosate (3%) or triclopyr (3%) may be sprayed onto leaves. This can be done anytime during the growing season, but may be best in the early fall when native plants are dormant, but the target plant is still green and physiologically active. When applying herbicide to a plant with waxy leaves, consider adding 0.5% non-ionic surfactant to the herbicide mix if recommended on the herbicide label.
USE PESTICIDES WISELY: Always read the entire pesticide label carefully, follow all mixing and application instructions and wear all recommended personal protective gear and clothing. Contact your state department of agriculture for any additional pesticide use requirements, restrictions or recommendations.