Description

Oriental bittersweet is a dioeciousHaving the male and female reproductive organs on separate plants (of the same species) rather than different parts of the same plant. perenniala plant whose growth dies down annually but whose roots or other underground parts survive, deciduousa shrub or tree which sheds its leaves annually vine that can grow up to 60 feet. The stems of Celastrus orbiculatus have dark brown to brown striatedmarked with long, thin parallel streaks bark. The twigs are dark brown, brown or light gray and are smooth and glabroussmooth; free from hairs. Stems can reach 4 inches in diameter. The buds along the stem are axillary. The leaves are alternate and spiral evenly around the stem. They have a light green color and are widely elliptic, ovate to obovate, or circular. The flowers, which bloom in May to early June, are axillary in their position on the stem. There are 3-4 small greenish flowers per inflorescence and they are 0.07-0.15 inches long and 0.1-0.2 inches wide. The fruits of Celastrus orbiculatus are produced from July to October, are globose in shape, 0.24-0.35 inches long and 0.28-0.4 inches wide, and are yellow in color with a fleshy red aril surrounding them. The fruits split open at maturity revealing 3 red-orange axils that contain the seeds. The yellow ovary walls begin to fall from the fruits after frost.

Habitat

Oriental bittersweet grows most profusely in the sun, but can tolerate dense shade. It grows in disturbed woodlands, fields, along the coast and in salt marshes. Fence rows (where birds sit and disperse the seeds), roadways and railroads are also prime habitat for C. orbiculatus. It will grow over anything that it comes upon.

History and Introduction

Celastrus orbiculatus is native to East Asia: Japan, Korea and China. It was introduced to the United States from China as an ornamental around 1860. It reached Connecticut as early as 1916, and was collected from Massachusetts in 1919 and New Hampshire in 1938. It is now established in all the states of New England.

Threats

Oriental bittersweet causes major damage to native plants by girdlingthe strangling of a tree branch or tree trunk by something wrapped around it (such as Oriental Bittersweet), which chokes off the flow of nutrients. Mechanical damage of trees and other plants is also caused by the additional weight added onto the branches, causing the branches to break. The vigorous growth of the vine also shades other species. Another threat is the possibility of it displacing American bittersweet.

Dispersal Methods

The fruits of oriental bittersweet are most often dispersed by birds. If the plant is near water, the fruit can float and be moved downstream. People often use this plant for wreaths and floral arrangements in the fall because of its colorful fruits. Oftentimes, after the plant is used it is thrown away, and the fruits are also dispersed this way.

Control

Manual, mechanical, and chemical control methods are all effective in removing and killing oriental bittersweet. Employing a combination of methods often yields the best results and may reduce potential impacts to native plants, animals and people. The method you select depends on the extent and type of infestation, the amount of native vegetation on the site, and the time, labor and other resources available to you. Whenever possible and especially for vines climbing up trees or buildings, a combination of cutting followed by application of concentrated systemic herbicide to rooted, living cut surfaces is likely to be the most effective approach. For large infestations spanning extensive areas of ground, a foliar herbicide may be the best choice rather than manual or mechanical means which could result in soil disturbance.

Mechanical

Hand pull by the roots and removed from the site, preferably before fruiting; if fruits are present, vines should be bagged and disposed of in a landfill, or left in the bags and allowed to bake in the sun long enough to kill the seeds. 

Small infestations can be hand-pulled but the entire plant should be removed including all the root portions. If fruits are present, the vines should be bagged in plastic trash bags and disposed of in a landfill. Always wear gloves and long sleeves to protect your skin from poison ivy and barbed or spined plants. For climbing vines, first cut the vines near the ground at a comfortable height to kill upper portions and relieve the tree canopy. Vines can be cut using pruning snips or pruning saw for smaller stems or a hand axe or chain saw for larger vines. Try to minimize damage to the bark of the host tree. Rooted portions will remain alive and should be pulled, repeatedly cut to the ground or treated with herbicide. Cutting without herbicide treatment will require vigilance and repeated cutting because plants will resprout from the base.

Chemical

Herbicides, such as glyphosatea widely used herbicide that can kill certain weeds and grasses, it works by blocking an enzyme essential for plant growth (e.g., Roundup) or triclopyrherbicide used to control both broadleaf and woody plants (e.g., Garlon) are successful. These herbicides are taken into the roots and kill the entire plant.