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Oriental bittersweet, Asian bittersweet

(Celastrus orbiculatus, Celastrus loeseneri)

Photo of Oriental bittersweet
Photo credit: S. Kelly Kearns

Perennial, woody climbing vine. A Prolific producer of red-orange berries. Stems may reach six inches in diameter. Male and female flowers usually borne on separate plants.

Overview

Other names for this plant 
  • Common names: Asian bittersweet, Asian loeseneri bittersweet, Japanese bittersweet, round leaf bittersweet
  • Scientific names: Celastrus rosthornianus var. loeseneri, C. orbiculata; C. articulatus
Ecological threat
  • Invades forests, woodlands, fields, hedge-rows and coastal areas and can grow in open sites or under a closed forest canopy.
  • Oriental bittersweet grows rapidly and is tolerant of a wide range of habitats.
  • May damage trees by girdling trunks with its woody stem, shading out the tree’s leaves or weighing down its crown making it susceptible to damage from wind or heavy snowfall.
  • It is widely planted as an ornamental vine and is sometimes planted accidentally when mistaken for American bittersweet.
Overview map of Oriental bittersweet classification in WI
Oriental bittersweet is Restricted (orange counties). Asian bittersweet is Prohibited.

Classification in Wisconsin: Restricted, Prohibited

Species Assessment Groups (SAG) were assembled to recommend a legal classification for each species considered for NR 40. The recommendation for Oriental bittersweet was based upon this literature review [PDF] developed by the department. The recommendation for Asian bittersweet was based upon this literature review [PDF] developed by the department.

Identification

Leaves: Alternate, glossy and round with a pointing tip and shallow-toothed margins, two to five inches long.

Flowers: Small, inconspicuous, five-petaled, greenish-yellow flowers in clusters of three to seven at leaf axils. Most plants are dioecious.

Fruits & seeds: Showy, round capsules, clustered in leaf axils. Green in summer, yellow-orange in fall. Split open at maturity to reveal three red-orange, fleshy fruits, each containing one or two seeds. Dispersed by birds and small mammals.

Roots: Spreading underground roots can sprout to form new stems.

Similar species: American bittersweet (Celastrus scandens; native) has fewer, larger clusters of fruits or flowers, which are terminal rather than at leaf axils. Its leaves are less rounded and nearly twice as long as wide. Hybrids of the two occur, which may make identification difficult.

Control

Mechanical
  • Dig out or hand pull seedlings.
  • Cut the base of the vines strangling trees, allowing upper foliage to die back.
Chemical
  • Basal bark with triclopyr ester plus a surfactant.
  • Cut stem treatment with glyphosate or triclopyr amine.
  • Foliar spray with triclopyr ester or triclopyr amine plus a non-ionic surfactant.

For more information on control techniques, visit the bittersweet factsheet [exit DNR] by University of Wisconsin-Extension.

Photos

View Oriental bittersweet pictures in our photo gallery.

Resources

Sources for content
  • Czarapata, Elizabeth; Invasive Plants of the Upper Midwest: an illustrated guide to their identification and control. University of Wisconsin Press. 2005. Pg. 45-46
  • Swearingen, Jil M. Plant Conservation Alliance, Alien Plant Working Group. Least Wanted: Oriental bittersweet [exit DNR]. Last updated June 2006.
More information