Celastrus orbiculatus Thunb.
Common Name: ORIENTAL BITTERSWEET
Coefficient of Conservatism: *
Coefficient of Wetness: 5
Wetness Index: UPL
Physiognomy: Ad W-Vine

Celastrus orbiculatus A. A. Reznicek

A native of Asia, sometimes cultivated; it can be aggressive when escaped. A vigorous, large, high-climber, it is a serious invasive of forests and areas near habitation in southern Michigan, capable of smothering trees and shrubs. First collected in 1976 in St. Joseph Co.

Vegetative material of C. orbiculatus can sometimes be difficult to distinguish from C. scandens. More characters are provided by Leicht-Young et al. (2008).

Invasion by this species appears to be marked also by a decline in the native Celastrus scandens in the invaded zone. In addition, the two hybridize, and hybrids are known from Michigan; first reported from Warren Dunes State Park by Zaya et al., (2015). Their frequency is unclear as yet, but flowering Celastrus should be carefully examined. Hybrids can be expected to be as vigorous as C. orbiculatus, and bear flowers both in terminal racemes or panicles and in cymes in the axils of full-sized foliage leaves. Zaya et al., (2015) illustrate this, as well as other diagnostic features of the fruits. 

Locations

Allegan County
Berrien County
Branch County
Calhoun County
Kalamazoo County
Kent County
Keweenaw County
Leelanau County
Lenawee County
Livingston County
Macomb County
Marquette County
Mason County
Mecosta County
Muskegon County
Oakland County
Ottawa County
St. Clair County
St. Joseph County
Washtenaw County
Wayne County

Citation:

MICHIGAN FLORA ONLINE. A. A. Reznicek, E. G. Voss, & B. S. Walters. February 2011. University of Michigan. Web. December 7, 2019. https://www.michiganflora.net/species.aspx?id=801.