Celastrus orbiculatus (Asiatic bittersweet)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Growth Stages
- Biology and Ecology
- Soil Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Social Impact
- Risk and Impact Factors
- Uses List
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Celastrus orbiculatus Thunb.
Preferred Common Name
- Asiatic bittersweet
Other Scientific Names
- Celastrus articulatus Thunb.
- Celastrus orbiculata Loes.
International Common Names
- English: Asian bittersweet; Chinese bittersweet; Japanese bittersweet; oriental bittersweet
Local Common Names
- Germany: Baumwürger, Rundblättriger
- Japan: tsuru-ume-mo-doki
- New Zealand: climbing spindleberry
- USA: round-leaved bittersweet
- CELOR (Celastrus orbiculatus)
Summary of InvasivenessTop of page
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Celastrales
- Family: Salacia
- Genus: Celastrus
- Species: Celastrus orbiculatus
Notes on Taxonomy and NomenclatureTop of page
DescriptionTop of page
Plant TypeTop of page
Vine / climber
DistributionTop of page
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.Last updated: 17 Feb 2021
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Japan||Present||Present based on regional distribution.|
|Russia||Present||Present based on regional distribution.|
|-Russian Far East||Present||Native|
|United Kingdom||Present, Few occurrences||Introduced||1891|
|Canada||Present||Present based on regional distribution.|
|United States||Present||Present based on regional distribution.|
|-Connecticut||Present, Widespread||Introduced||Invasive||Original citation: Dreyer, 1987|
|-New Hampshire||Present, Localized||Introduced||Invasive|
|-New Jersey||Present, Widespread||Introduced||Invasive|
|-New York||Present, Widespread||Introduced||Invasive|
|-North Carolina||Present, Widespread||Introduced||Invasive|
|-Rhode Island||Present, Widespread||Introduced||Invasive|
|-West Virginia||Present, Localized||Introduced||Invasive|
History of Introduction and SpreadTop of page
Risk of IntroductionTop of page
HabitatTop of page
Habitat ListTop of page
|Terrestrial||Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Managed||Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Natural forests||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|Terrestrial||Natural / Semi-natural||Riverbanks||Present, no further details||Harmful (pest or invasive)|
|Littoral||Coastal areas||Present, no further details||Harmful (pest or invasive)|
Hosts/Species AffectedTop of page
Growth StagesTop of page
Biology and EcologyTop of page
The chromosome number is n=23 (Bowden, 1945). Artificial hybridization with the North American native C. scandens has been documented twice. When White and Bowden (1947) crossed the species, the resulting offspring were few in number and less vigorous than either parent. Pooler et al. (2002) crossed C. scandens (female parent) with C. orbiculatus and found classic hybrid vigour; the resulting plants had less seed dormancy and were more vigorous than progeny of C. scandens alone. Dreyer et al. (1987) found much higher pollen and seed viability in C. orbiculatus compared to C. scandens. Given the decline in C. scandens populations and the concurrent rise in C. orbiculatus populations, the possibility of introgressive hybridization has been speculated (Dreyer et al., 1987; Pooler et al., 2002; Steward et al., 2003). Plants apparently intermediate between these two species have occasionally been noted in the field (Dreyer et al., 1987) but not in great numbers.
Physiology and Phenology
Flowers bloom in late May to early June in Connecticut, USA, and fruit ripen in September and remain on the vine through much of the winter. Leaves are fully expanded by late May, begin to yellow in mid-September and fall by mid to late October. For a detailed study of photosynthesis and water relations in C. orbiculatus refer to Clement et al. (1991).
Plants are usually dioecious (Brizicky, 1964) and occasionally monoecious, i.e. with both male and female flowers on the same vine (Hou, 1955) or polygamo-dioecious, i.e. with both unisexual and perfect flowers on the same plant (Gleason and Cronquist, 1991). Brizicky (1964) notes Hymenopterous insects, especially bees, are its main pollinators, and Wyman (1950) also found wind pollination to be effective. Fruit dispersal is generally thought to be by birds and small mammals (Wheeler, 1987). Seeds require cold stratification for germination. Patterson (1974) found germination percentages of 30-95% with highest germination under low light intensities. Dreyer et al. (1987) found an average of 71% germination with seed collected in Connecticut, USA and confirmed higher germination at lower light levels. In a 3-year seed bank persistence study of native and non-native congeneric plants, Van Clef and Stiles (2001) found that both C. scandens and C. orbiculatus had negligible germination after the first year. C. orbiculatus produces root suckers prolifically, and thus a single individual can expand to a dense thicket in a relatively short time. Small pieces of root left during clearing operations resprout quickly to form new plants.
C. orbiculatus germinates well in low light conditions found beneath existing plant cover. Fastest growth is attained in high light locations, with plants suppressed by shade ready to take advantage of canopy gaps caused by wind or other disturbance events. At a forest site in the Appalachian Mountains of North Carolina, USA (McNab and Loftis, 2002) presence of the vine was associated with mesic soil conditions, overstorey canopy gaps, locations with past timber harvests, and forest floor scarification. In Massachusetts, USA, Silveri et al. (2001) found optimal growth in moist soil under high irradiance, and in a forest disturbed 14 years previously by logging, C. orbiculatus invaded 2 years after the harvest and the vines were more abundant on the former logging roads than the surrounding logged area. Sinclair et al. (1987) list this plant as intolerant of flooding or waterlogged soils.
A number of birds, including black-capped chickadees, the northern mockingbird, European starling and blue jay all feed on C. orbiculatus fruit during the winter in the USA.
Soil TolerancesTop of page
Special soil tolerances
Notes on Natural EnemiesTop of page
Means of Movement and DispersalTop of page
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page
Environmental ImpactTop of page
Impact: BiodiversityTop of page
Social ImpactTop of page
Risk and Impact FactorsTop of page
- Proved invasive outside its native range
- Highly adaptable to different environments
- Highly mobile locally
- Has high reproductive potential
- Negatively impacts agriculture
- Negatively impacts tourism
- Reduced amenity values
- Reduced native biodiversity
- Competition - monopolizing resources
- Difficult/costly to control
UsesTop of page
Uses ListTop of page
Similarities to Other Species/ConditionsTop of page
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.Cultural Control
Goats and sheep have been observed to effectively control C. orbiculatus infestations in the USA.
Repeated cutting or mowing, where possible and appropriate, will suppress and eventually eliminate C. orbiculatus. In Connecticut, USA this must be more often than monthly during the growing season.
Dreyer (1988) reported that the use of herbicides was successful for controlling dense, low patches of C. orbiculatus. Vegetation in the entire area is cut to the ground early in the growing season and allowed to regrow, and approximately one month later, foliar applications of a triclopyr ester or salt applied by backpack sprayer results in a 100% rootkill of C. orbiculatus. No off-target damage or root uptake by adjacent plants has been noted in many years of using this technique. The same study found foliar applications of glyphosate and amitrole were both ineffective in killing the roots of C. orbiculatus. Hutchison (1992) reports that foliar applications of a mixture of 2,4-D and triclopyr to C. orbiculatus will effectively reduce the population when applied in mid to late October. Ahrens (1987) noted complete control with tripclopyr ester and imazapyr, and partial control with glyphosate. Dreyer (2001) modified the mow and spray technique previously mentioned for use on larger areas with tractor-mounted agricultural equipment to test for the minimum effective dose of triclopyr, and the effect of spray date. Late growing season (early September) applications as low as 0.5% triclopyr in water effectively killed C. orbiculatus, whereas early summer applications of 1% triclopyr provided significant, but not complete, rootkill. An additional advantage to using triclopyr is that, unlike the commonly used glyphosate, it does not kill monocotyledonous plants and, when present, these plants will remain to prevent soils from being completely denuded and potentially eroded. Work is currently underway in Connecticut, USA to test the effectiveness of treating large cut stems of C. orbiculatus with herbicides.
No biological control of C. orbiculatus has been recorded.
Control of C. orbiculatus along roadsides would go a long way toward decreasing the seed source. In heavy infestations on fields and shrublands, an initial herbicide treatment to rootkill existing plants followed by periodic controlled burning (Niering and Dreyer, 1989) or periodic selective re-spraying should prevent re-establishment by seed.
ReferencesTop of page
Aherns J, 1987. Herbicides for Control of Oriental Bittersweet. Proceedings of the Northeastern Weed Science Society, 41:167-170.
Brizicky G, 1964. The genera of Celastrales in the Southeastern United States. Journal of the Arnold Arboretum, 45:206-218.
Clement C; Warren R; Dreyer G; Barnes P, 1991. Photosynthesis, water relations and fecundity in the woody vines American and Oriental bittersweet (Celastrus scandens and C. orbiculatus). Annual Meeting Bot. Soc. Amer. Poster Abstract in American Journal of Botany, 78(6):134-135.
Dreyer G, 2001. Oriental Bittersweet Control Project, Sachuest Point National Wildlife Refuge. Unpublished Final Report. Produced under contract to the US Fish and Wildlife Service.
Dreyer G; Baird L; Fickler C, 1987. Celastrus scandens and Celastrus orbiculatus: Comparisons of reproductive potential between a native and an introduced woody vine. Bull. Torrey Bot. Club 114(3):260-264.
Dreyer GD, 1988. Efficacy of triclopyr in rootkilling oriental bittersweet (Celastrus orbiculatus Thunb.) and certain other woody weeds. Proceedings, 42nd annual meeting of the Northeastern Weed Science Society, 120-121
Fike J; Niering WA, 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; 2 pp. of ref.
Gleason H, 1952. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada, Volume 2. New York, USA: The New York Botanical Garden and Hafner Press.
Gleason HA; Cronquist A, 1991. Manual of Vascular Plants of Northeastern United States and adjacent Canada. Second edition. New York, USA: The New York Botanical Garden.
Holmgren N, 1988. The Illustrated Companion to Gleason and Cronquist's Manual. Illustrations of the Vascular Plants of Northeastern United States and Adjacent Canada. Bronx, NY, USA: The New York Botanical Garden.
Hou D, 1955. A revision of the genus Celastrus. Annals of the Missouri Botanical Garde,n 42:215-302.
McNab WH; Loftis DL, 2002. Probability of occurrence and habitat features for oriental bittersweet in an oak forest in the southern Appalachian mountains, USA. Forest Ecology and Management, 155(1/3):45-54; 27 ref.
Niering W; Dreyer G, 1989. Effects of prescribed burning on Andropogon scoparius in postagricultural grasslands in Connecticut. American Midland Naturalist, 122:88-102.
Owen SJ, 1996. Ecological weeds on conservation land in New Zealand: A database. Department of Conservation, Wellington, New Zealand: DOC Science Publications. http://www.hear.org/weedlists/other_areas/nz/nzecoweeds.htm.
Pooler MR; Dix RL; Feely J, 2002. Interspecific hybridizations between the native bittersweet, Celastrus scandens, and the introduced invasive species, C. orbiculatus. Southeastern Naturalist, 1(1):69-76; 17 ref.
Rheder A, 1940. Manual of Cultivated Trees and Shrubs. Second Edition. New York, USA: MacMillan Publishing Co., Inc.
Scoggan HJ, 1978. The flora of Canada, Part 3 - Dicotyledoneae (Saururaceae to Violaceae). Ottawa, Quebec, Canada: National Museum of Natural Sciences, National Museums of Canada, 568 pp.
Silveri A; Dunwiddie P; Michaels H, 2001. Logging and edaphic factors in the invasion of an Asian woody vine in a mesic North American forest. Biological Invasions, 3:379-389.
Sinclair W; Lyon H; Johnson W, 1987. Diseases of Trees and Shrubs. Ithaca, NY, USA: Cornell University Press.
Soper J; Heimburger M, 1985. Shrubs of Ontario. Life Sciences Miscellaneous Publications. Second revised printing. Toronto, Ontario, Canada: The Royal Ontario Museum.
Steward A., Clemants S, Moore G, 2003. The concurrent decline of the native Celastrus scandens and spread of the non-native Celastrus orbiculatus in the New York Metropolitan area. Journal of the Torrey Botanical Society, 130 (2): 143-146.
USDA-ARS, 2003. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx
Van Clef M; Stiles E, 2001. Seed longevity in three pairs of native and non-native congeners: assessing invasive potential. Northeastern Naturalist, 8(3):301-310.
Wheeler L, 1987. Oriental bittersweet: avian dispersal in winter in relation to other species of fruiting plants. Undergraduate Individual Study Report. Zoology Department, Connecticut College, New London, USA.
White O; Bowden W, 1947. Oriental and American bittersweet hybrids. Journal of Heredity, 38(4):125-127.
Wyman D, 1950. Fruiting habits of certain ornamental plants. Arnoldia, 10(13):81-85.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Dreyer G, 2001. Oriental Bittersweet Control Project, Sachuest Point National Wildlife Refuge. In: Unpublished Final Report. Produced under contract to the US Fish and Wildlife Service,
Hou D, 1955. A revision of the genus Celastrus. In: Annals of the Missouri Botanical Garden, 42 215-302.
Owen S J, 1996. Ecological weeds on conservation land in New Zealand: a database. In: Ecological weeds on conservation land in New Zealand: a database, Department of Conservation, Wellington, New Zealand: DOC Science Publications. http://www.hear.org/weedlists/other_areas/nz/nzecoweeds.htm
Scoggan HJ, 1978. The flora of Canada, Part 3 - Dicotyledoneae (Saururaceae to Violaceae)., Ottawa, Quebec, Canada: National Museum of Natural Sciences, National Museums of Canada, 568. 568 pp.
Soper J, Heimburger M, 1985. Shrubs of Ontario. Life Sciences Miscellaneous Publications., Toronto, Ontario, Canada: The Royal Ontario Museum.
Takada H, 2002. Parasitoids (Hymenoptera: Braconidae, Aphidiinae; Aphelinidae) of four principal pest aphids (Homoptera: Aphididae) on greenhouse vegetable crops in Japan. Applied Entomology and Zoology. 37 (2), 237-249. DOI:10.1303/aez.2002.237
USDA-ARS, 2003. Hedychium flavescens. In: Germplasm Resources Information Network (GRIN). Online Database, Beltsville, USA: National Germplasm Resources Laboratory. http://www.ars-grin.gov/cgi-bin/npgs/html/tax_search.pl
Distribution MapsTop of page
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