COMMON NAME

Oriental bittersweet
Asiatic bittersweet
Round-leaved bittersweet

FULL SCIENTIFIC NAME

Celastrus orbiculatus Thunb.

FAMILY NAME COMMON

Staff-Tree family

FAMILY SCIENTIFIC NAME

Celastrus orbiculatus

IMAGES

Vine growning up trunk	Close-up of staminate flowers	Close-up of pistillate flowers
Incursion	Close-up of fruits	Fruit in tree
Seedlings

NOMENCLATURE/SYNONYMS

Synonyms: Celastrus articulatus Thunb.

DESCRIPTION

Botanical Glossary

Celastrus orbiculatus is a dioecious (or polygamodioecious), perennial, deciduous vine that can grow up to 17.3 m (60 ft.). The stems of Celastrus orbiculatus have dark brown to brown striated bark. The twigs are dark brown, brown or light gray and are smooth and glabrous. Stems can reach 10 cm (4 in.) 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 1.8-4 mm (0.07-0.15 in.) long and 2.2-5.5 mm (0.1-0.2 in.) wide. The fruits of Celastrus orbiculatus are produced from July to October, are globose in shape, 6-9 mm (0.24-0.35 in.) long and 7-10 mm (0.28-0.4 in.) wide, and are yellow in color with a fleshy red aril surronding 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. Page References Bailey 631, Fernald 984, Gleason & Cronquist 328, Holmgren 308, Magee & Ahles 716, Newcomb 326. See reference section below for full citations.

SIMILAR SPECIES

Celastrus scandens L. (American bittersweet)
There is also hybrid between C. orbiculatus and C. scandens Celastrus orbiculatus is often confused with native bittersweet (C. scandens). The main feature that differentiates between the two plants is the location of the inflorescence. The inflorescence of C. scandens is located terminally and not axillary on the stems. Another feature (which is not always consistent) is the color of the ovary walls. In the fall the ovary walls of C. orbiculatus are yellow while those of C. scandens are a darker orange color that does not contrast as much with the red arils.

REPRODUCTIVE/DISPERSAL MECHANISMS

The fruits of Celastrus orbiculatus are most often dispersed by birds. If the plant is near water, the fruit can float and be moved downstream.

DISTRIBUTION

Celastrus orbiculatus is native to East Asia: Japan, Korea and China. It is presently reported from Louisiana to Maine and West to Iowa. It is established in all the states of New England.

HISTORY OF INTRODUCTION IN NEW ENGLAND

Celastrus orbiculatus 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.

HABITATS IN NEW ENGLAND

Celastrus orbiculatus 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.

THREATS

Celastrus orbiculatus causes major damage to native plants by girdling. 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 (C. scandens). Celastrus scandens does not exhibit this aggressive growth, but it can hybridize with C. orbiculatus. People often use C. orbiculatus for wreathes and floral arrangements in the fall because of its colorful fruits. Oftentimes, after the plant is used it thrown away, and the fruits are dispersed this way.

MANAGEMENT LINKS

Illinois Natural History Survey
General description and management guidelines

Plant Conservation Alliance
Fact sheet including management information

The Nature Conservancy

The Connecticut Invasive Plant Working Group Invasive Plant Management Guide
Comprehensive management information

DOCUMENTATION NEEDS

Documentation required: Photograph of habit, inflorescence.
Best time for documentation: Summer, fall.

ADDITIONAL INFORMATION

Integrated Taxonomic Information System
Taxonomic information about the species

The PLANTS Database
General information

Plant Conservation Alliance
General information and management

Department of Conservation and Recreation - Virginia Native Plant Society
General information

The Nature Conservancy
General information including control

Brooklyn Botanic Garden
General information including a photograph

Salisbury University Arboretum
Photographs

Bailey, L. H.  1949.  Manual of Cultivated Plants.  Macmillan, New York.

Dreyer, G.D. 1988. Efficacy of triclopyr in rootkilling Oriental bittersweet (Celastrus orbiculatus Thunb.) and certain other woody weeds. Proceedings of the Northeastern Weed Science Society 42, 120-121. 

Dreyer,G., L. Baird and C. Fickler. 1987. Celastrus scandens and Celastrus orbiculatus: Comparisons of reproductive potential between a native and an introduced woody vine. Bulletin of the Torrey Botanical Club 114(3):260-264.

Fernald, M.L. 1950. Gray's Manual of Botany 8th ed. American Book Co., Boston.

Fike, J., W.A. Niering. 1999. Four decades of old field vegetation development and the role of Celastrus orbiculatus in the northeastern United States. Journal of Vegetation Science 10 (4): 483-492.

Fire Conference 2000.  Proceedings of the Invasive Species Workshop: The Role of Fire in the Control and Spread of Invasive Species. The First National Congress on Fire Ecology, Prevention, and Management.  Tall Timbers Research Station, Miscellaneous Publication No. 11.

Gleason, H.A. and A.C. Cronquist. 1991. Manual of Vascular Plants of the Northeastern United States and Adjacent Canada. 2nd ed. New York Botanical Garden, Bronx, New York.

Greenberg, C.H., L.H. Smith and D.J. Levey. 2001. Fruit fate, seed germination and growth of an invasive vine - an experimental test of "sit and wait" strategy. Biological Invasions 3, 363-372.

Holmgren, N.H. 1998. Illustrated Companion to Gleason and Cronquist's Manual.  New York Botanical Garden, Bronx, New York.

Hutchison, M. 1992. Vegetation management guideline: round-leaved bittersweet (Celastrus orbiculatus Thunb.). Natural Areas Journal 12, 161-166.

Leicht, S.A. 2005.  The comparative ecology of an invasive Bittersweet species (Celastrus orbiculatus) and its native congener (C. scandens). Ph.D. thesis, University of Connecticut, Storrs, Connecticut.

Lutz, H.J. 1943. Injuries to trees caused by Celastrus and Vitis. Bulletin of the Torrey Botanica lClub  70, 436-439.

Magee, D.W and H.E. Ahles. 1999.  Flora of the Northeast. University of Massachusetts Press, Amherst.

McNab, W. H. and M. Meeker. 1987.  Oriental bittersweet: a growing threat to hardwood silviculture in the Appalachians.  Northern Journal of Applied Forestry 4:174-177.

Newcomb, N. 1977.  Newcomb's Wildflower Guide.  Little Brown, Boston.

Pooler, M.R., R.L. Dix and J. Feely. 2000. Interspecific hybridizations between the native bittersweet Celastrus scandens and the introduced invasive species C. orbiculatus. Hortscience 35 (3): 395.

Robertson, D. J., M.C. Robertson and T. Tague.  1994.  Colonization dynamics of four exotic plants in a Northern Piedmont Natural Area.  Bulletin of the Torrey Botanical Club 121(2):107-118.

Silveri, A., P.W. Dunwiddie and H.J. and Michaels. 2001. Logging and edaphic factors in the invasion of an Asian woody vine in a mesic North American forest. Biological Invasions 3: 379-389.

Silveri, A., H. Michaels, P. Dunwiddie. 1996. A logging-facilitated invasion of Celastrus orbiculatus (Oriental bittersweet) in a rich mesic forest in Massachusetts. Bulletin of the Ecological Society of America 77 (3 SUPPL. PART 2): 409.

Tibbetts, T.J. and F.W. Ewers. 1998. Is increased water transport responsible for the invasive nature of Celastrus orbiculatus? Specific conductivity and root pressure in temperate lianas: Exotic Celastrus orbiculatus versus native Vitis riparia. American Journal of Botany 85 (6): 52.

USDA, NRCS.  2001.  The PLANTS Database, Version 3.1. (http://plants.usda.gov).  National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

White, O.E. and Bowden, W.M. 1947. Oriental and American bittersweet hybrids. Journal of Heredity 38, 125-127.