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FACT SHEET: ORIENTAL BITTERSWEET

Oriental Bittersweet 

Celastrus orbiculatus Thunb. 

Staff-tree family (Celastraceae) 

NATIVE RANGE 

Eastern Asia, Korea, China and Japan 

DESCRIPTION 

Oriental bittersweet is a deciduous woody perennial plant which grows 

as a climbing vine and a trailing shrub. Stems of older plants 4 inches 

in diameter have been reported. The leaves are alternate, glossy, 

nearly as wide as they are long (round), with finely toothed margins. 

There are separate female (fruiting) and male (non-fruiting) plants. 

Female plants produce clusters of small greenish flowers in axillary 

clusters (from most leaf axils), and each plant can produce large 

numbers of fruits and seeds. The fruits are three-valved, yellow, globular capsules that at maturity split open to reveal 

three red-orange, fleshy arils each containing one or two seeds. The abundance of showy fruits have made Oriental 

bittersweet extremely popular for use in floral arrangements. 

NOTE: Because Oriental bittersweet can be confused with our native American bittersweet (Celastrus scandens) which is 

becoming less and less common, it is imperative that correct identification be made before any control is begun. American 

bittersweet produces flowers (and fruits) in single terminal panicles at the tips of the stems; flower panicles and fruit 

clusters are about as long as the leaves; the leaves are nearly twice as long as wide and are tapered at each end. 

Oriental bittersweet produces flowers in small axillary clusters that are shorter than the subtending leaves and the leaves 

are very rounded. Comparing the two, American bittersweet has fewer, larger clusters of fruits whereas Oriental 

bittersweet is a prolific fruiter with lots and lots of fruit clusters emerging at many points along the stem. Unfortunately, 

hybrids of the two occur which may make identification more difficult. 

ECOLOGICAL THREAT 

Oriental bittersweet is a vigorously growing vine that climbs over and smothers vegetation which may die from excessive 

shading or breakage. When bittersweet climbs high up on trees the increased weight can lead to uprooting and blow-over 

during high winds and heavy snowfalls. In addition, Oriental bittersweet is displacing our native American bittersweet 

(Celastrus scandens) through competition and hybridization. 

DISTRIBUTION IN THE UNITED STATES 

Oriental bittersweet currently occurs in a number of states from New York to 

North Carolina, and westward to Illinois. It has been reported to be invasive in 

natural areas in 21 states (CT, DE, IL, IN, KY, MA, MD, ME, MI, MO, NC, NH, 

NJ, NY, PA, RI, TN, VA, VT, WI, and WV) and at least 14 national parks in the 

eastern U.S. 

HABITAT IN THE UNITED STATES 

Oriental bittersweet infests forest edges, woodlands, fields, hedgerows, coastal 

areas and salt marsh edges, particularly those suffering some form of land 

disturbance. While often found in more open, sunny sites, its tolerance for 

shade allows oriental bittersweet to invade forested areas. 

BACKGROUND 

Introduced into the U.S. in the 1860s as an ornamental plant, oriental bittersweet is often associated with old homesites, 

from which it has escaped into surrounding natural areas. Oriental bittersweet is still widely planted and maintained as an 

ornamental vine, further promoting its spread. 
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BIOLOGY & SPREAD 

Oriental bittersweet reproduces prolifically by seed, which is readily dispersed to new areas by many species of birds 

including mockingbirds, blue jays and European starlings. The seeds germinate in late spring. It also expands vegetatively 

through root suckering. 

MANAGEMENT OPTIONS 

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. 

Biological 

No biological controls are currently available for this plant. 

Chemical

Systemic herbicides like triclopyr (e.g., Garlon® 3A and Garlon® 4) and glyphosate (e.g., Accord®, Glypro®, Rodeo®) are 

absorbed into plant tissues and carried to the roots, killing the entire plant within about a week. This method is most 

effective if the stems are first cut by hand or mowed and herbicide is applied immediately to cut stem tissue. Herbicide 

applications can be made any time of year as long as temperatures are above 55 or 60 degrees Fahrenheit for several 

days and rain is not expected for at least 24 hours. Fall and winter applications will avoid or minimize impacts to native 

plants and animals. Repeated treatments are likely to be needed. In areas where spring wildflowers or other native plants 

occur, application of herbicides should be conducted prior to their emergence, delayed until late summer or autumn, after 

the last killing frost occurs, or carefully targeted. Herbicidal contact with desirable plants should always be avoided. If 

native grasses are intermingled with the bittersweet, triclopyr should be used because it is selective for broad-leaved 

plants and will not harm grasses. Follow-up monitoring should be conducted to ensure effective control. 

Glyphosate products referred to in this fact sheet are sold under a variety of brand names (Accord®, Rodeo®, Roundup 

Pro® Concentrate) and in three concentrations (41.0, 50.2 and 53.8% active ingredient). Other glyphosate products sold 

at home improvement stores may be too dilute to obtain effective control. Triclopyr comes in two forms – triclopyr amine 

(e.g., Garlon® 3A, Brush-B-Gone®, Brush Killer®) and triclopyr ester (e.g., Garlon® 4, Pathfinder®, and Vinex®). 

Because Garlon® 3A is a water-soluble salt that can cause severe eye damage, it is imperative that you wear protective 

goggles to protect yourself from splashes. Garlon® 4 is soluble in oil or water, is highly volatile and can be extremely toxic 

to fish and aquatic invertebrates. It should not be used in or near water sources or wetlands and should only be applied 

under cool, calm conditions. 

Basal bark application 

Use a string trimmer or hand saw to remove some of the foliage in a band a few feet from the ground at comfortable 

height. To the exposed stems, apply a 20% solution of triclopyr ester (Garlon® 4) (2.5 quarts per 3-gallon mix) in 

commercially available basal oil with a penetrant (check with herbicide distributor) to vine stems. As much as possible, 

avoid application of herbicide to the bark of the host tree. This can be done year-round although efficacy may vary 

seasonally; temperatures should be above 50 degrees F for several days. 

Cut stem application 

Use this method in areas where vines are established within or around non-target plants or where vines have grown into 

the canopy. Cut each vine stem close to the ground (about 2 in. above ground) and immediately apply a 25% solution of 

glyphosate (e.g., Accord®) or triclopyr (e.g., Garlon® 3A) mixed with water to the cut surface of the stem. The glyphosate 

application is effective at temperatures as low as 40°F and a subsequent foliar application may be necessary. The 

triclopyr application remains effective at low temperatures (<60°F) as long as the ground is not frozen. A subsequent foliar 

application may be necessary to control new seedlings. Homeowners can apply products like Brush-B-Gone®, Brush 

Killer® and Roundup Pro® Concentrate undiluted to cut stems. Using a paint brush or a plastic spray bottle, apply 

herbicide to the cut surface. 
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Foliar application 

Use this method to control extensive patches of solid bittersweet. It may be necessary to precede foliar applications with 

stump treatments to reduce the risk of damaging non-target species. During foliar applications some of the herbicide is 

also absorbed through the stem for additional (basal bark) effect. Apply a 2% solution (8 oz per 3 gal. mix) triclopyr ester 

(Garlon® 4) or triclopyr amine (Garlon® 3A) mixed in water with a non-ionic surfactant to the leaves. In Rhode Island, 

concentrations as low as 1% in mid-summer and 0.05% in September have been very effective. Thoroughly wet the 

foliage but not to the point of runoff. The ideal time to spray is after much of the native vegetation has become dormant 

(October-November) to avoid affecting non-target species. A 0.5% concentration of a non-ionic surfactant is 

recommended in order to penetrate leaf cuticle. If the 2% rate is not effective try an increased rate of 3-5%. Ambient air 

temperature should be above 65°F. 

For dense, low patches of bittersweet another alternative is to cut the entire patch to the ground early in the growing 

season. About one month later, apply 1-2% solution of triclopyr ester (Garlon® 4) or triclopyr salt (Garlon® 3A) in water to 

the previously cut patch using a backpack sprayer. This method has resulted in complete rootkill of the bittersweet and no 

off-target damage or root uptake by adjacent plants. 

Manual and Mechanical 

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. 

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. 

NOTICE: mention of pesticide products on this page does not constitute endorsement of any material.

CONTACTS 

For more information on the management of Oriental bittersweet, please contact: 

• Glenn D. Dreyer, glenn.dreyer at conncoll.edu, (860) 439-2144 

• Sue Salmons, sue_salmons at nps.gov, (202) 342-1443 ext. 217 

• Jil Swearingen, jil_swearingen at nps.gov, (202) 342-1443 ext. 218 

SUGGESTED ALTERNATIVE PLANTS 

Several attractive native vines are available that provide nectar, seed and host plant material for butterflies, 

hummingbirds, and other wildlife. These include American bittersweet (Celastrus scandens) which is native to the eastern 

U.S. and should only be planted in areas where Oriental bittersweet is not well established or has been successfully 

controlled, to prevent hybridization with the native species. Other good alternatives include trumpet honeysuckle (Lonicera 

sempervirens), trumpet creeper (Campsis radicans), passionflower vine (Passiflora lutea), Dutchman's pipe (Aristolochia 

macrophylla) and native wisteria (Wisteria frutescens)*. 

*If you wish to plant wisteria, make certain that it is the native species. Two commonly planted ornamental wisterias, 

Chinese wisteria (Wisteria sinensis) and Japanese wisteria (Wisteria floribunda), are exotic and aggressive invaders. 

OTHER LINKS 

• http://www.invasive.org/search/action.cfm?q=Celastrus%20orbiculatus 

• http://nbii-nin.ciesin.columbia.edu/ipane/icat/browse.do?specieId=27

AUTHOR 

Jil M. Swearingen, National Park Service, Washington, DC 
2 May 2006 Page 4 of 4 

Plant Conservation Alliance®s Alien Plant Working Group 

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REVIEWERS 

Glenn D. Dreyer 

PHOTOGRAPH 

Jil M. Swearingen, National Park Service, Washington, DC 

REFERENCES 

Dirr, Michael A. 1990. Manual of wody landscape plants: their identification, ornamental characteristics, culture, 

propagation and uses. Stipes Publishing Company, Champaign, IL. 

Dreyer, G. 1988. Efficacy of triclopyr in rootkilling Oriental bittersweet and certain other woody weeds. Proceedings of the 

Northeastern Weed Science Society Vol. 42:120-121. 

Gleason, H.A. and A. Cronquist. 1991. Manual of vascular plants of northeastern United States and adjacent Canada, 2nd 

ed. New York Botanical Garden. pp 328-9. 

Harty, Francis M. 1993. How Illinois kicked the exotic species habit. Pp. 195-209. In B.N. McKnight (ed.), Biological 

Pollution, Indiana Acad. Sci., Indianapolis, IN. 261 pp. 

Hutchinson, M. 1992. Vegetation management guideline: round-leaved bittersweet (Celastrus orbiculatus). Natural Areas 

Journal 12:161. 

McNab, W.H. and M. Meeker. 1987. Oriental bittersweet: a growing threat to hard-wood silviculture in the Appalachians. 

Northern Journal of Applied Forestry 4:174-177. 

Shepard, C. 1996. Invasive Plant Information Sheet: Asiatic Bittersweet (Celastrus orbiculatus Thunb.). The Nature 

Conservancy, Connecticut Chapter, Hartford, CT. 

Southeast Exotic Pest Plant Council. 2003. Invasive Plant Manual. http://www.invasive.org/eastern/eppc/bittersweet.html 

Swearingen, J. 2009. WeedUS Database of Plants Invading Natural Areas in the United States: Oriental Bittersweet 

(Celastrus orbiculatus). http://www.invasive.org/weedus/subject.html?sub=3012. 

The Nature Conservancy. Oriental Bittersweet: Element Stewardship Abstract. In: Wildland Weeds Management & 

Research Program, Weeds on the Web. http://www.imapinvasives.org/GIST/ESA/ 

USDA, NRCS. 2009. The PLANTS Database (http://plants.usda.gov). National Plant Data Center, Baton Rouge, LA 

70874-4490 USA. 

Virginia Native Plant Society. 1995. Invasive Alien Plant Species of Virginia: Oriental Bittersweet (Celastrus orbiculatus

Thunb.). Virginia Department of Conservation and Recreation. http://www.state.va.us/~dcr/dnh/invcela.htm