Celastrus orbiculatus (Oriental Bittersweet)

Plant Info
Also known as: Asian Bittersweet
Genus:Celastrus
Family:Celastraceae (Staff-tree)
Life cycle:perennial woody
Origin:Asia
Status:
  • Invasive - ERADICATE!
  • Noxious Weed
  • Prohibited or Restricted species
Habitat:part shade, sun; woodland edges, thickets, old fields
Bloom season:May - June
Plant height:10 to 60-foot vine
Wetland Indicator Status:GP: UPL MW: UPL NCNE: UPL
MN county distribution (click map to enlarge):Minnesota county distribution map
National distribution (click map to enlarge):National distribution map

Pick an image for a larger view. See the glossary for icon descriptions.

Detailed Information

Flower: Flower shape: 5-petals Cluster type: panicle Cluster type: raceme

[photo of flowers] Clusters of up to 7 stalked flowers (frequently 3), forming in the leaf axils of this year's side branches of older woody stems, occasionally also at the tip of a branch. Flowers are ¼ to 1/3 inch across with 5 green to yellowish petals and 5 green sepals. Male and female flowers are typically on separate plants, rarely on the same plant and rarely a plant will have perfect flowers (having both male and female parts). Male flowers have 5 stamens with creamy white tips (anthers); female flowers have a stout style with a 3-lobed stigma at the top. Flowers are on a slender, hairless stalk.

Leaves and stems: Leaf attachment: alternate Leaf type: simple

 [photo of leaves] Leaves are alternate, 2 to 5 inches long and 1½ to 3 inches inches wide, have rounded teeth around the edges, are smooth on the upper surface, and may have sparse hairs along the veins on the underside. The slender leaf stalk is about ¾ inch long.

[photo of leaves] Leaf shape is somewhat variable, nearly round to oval or may be broadest at the tip end. The tip is rounded, or with an abrupt sharp point, or with a short taper to a point. The base is rounded, slightly heart-shaped, or slightly tapering to the stalk. Woody branches are gray-brown to brown with scattered conspicuous white pores (lenticels); the trunk, which can be 4 inches in diameter, has more roughly textured bark. This vine has no tendrils; it twines around trees and other structures for support.

Fruit: Fruit type: berry/drupe Fruit type: capsule/pod

[photo of fruit] Fruit is round, about 1/3 inch across, initially green, the outer casing turning yellow in late summer then splits open to reveal a bright red, 3-sectioned berry-like fruit, each section containing 1 or 2 seeds.

Notes:

This is a Very Bad plant, brought into North America as an ornamental and escaped into the wild. It is a terrible pest plant in the eastern U.S. and is just getting started in Minnesota. It spreads by both seeds and rhizomes, suckering like mad and creating incredibly dense walls, blocking nearly all light from whatever used to grow beneath it. The vines wrap themselves around trees and can strangle them, or even bring them down from the sheer weight of its leafy arms. Incredibly, it is still sold as nursery stock in some areas. It should be banned in the U.S., but there is too much money to be made selling “exotic” plants, so there really is no stopping it. In Minnesota it is listed as an Eradication species, meaning the MN Department of Agriculture (MDA) has targeted it for extermination while it is still relatively few in number here. We'll just have to wait and see how that goes. Populations have been tracked on the Invasive Plant Atlas and EDDMaps. If you spot this plant in Minnesota you should tell MDA about it.

When not flowering or fruiting, it is very difficult to distinguish from the native American Bittersweet (Celastrus scandens) but there are a number of differences to aid in a positive ID.

  • When flowering, C. orbiculatus has mostly small clusters in the leaf axils of a branch where C. scandens will have one large cluster at the end of a branch.
  • C. orbiculatus flowers are typically greener with narrower petals than C. scandens.
  • The male flowers of C. orbiculatus have creamy white anthers where those of C. scandens are distinctly yellow.
  • The fruits of C. orbiculatus have a yellow casing, where fruits of C. scandens have an orange to red casing.
  • Newer woody stems of C. orbiculatus have obvious white lenticels, where C. scandens lenticels are less conspicuous.
  • C. orbiculatus leaves are generally rounder and proportionately broader than C. scandens , with C. scandens more finely serrated, but this is variable.
  • In early spring when plants are just starting to leaf out, C. orbiculatus leaves are mostly flat or folded in half, opening like a book, where C. scandens will have the leaf edges rolled up like a scroll, though leaves developing later in the season may not be so easily distinguished.

The images on this page show many of these comparisons.

The two species are apparently capable of hybridizing, but whether this actually occurs in the wild is unknown and there is very little information available on this subject. Buyer beware: American Bittersweet is also available in the nursery trade and some vendors advertise selling it, but turns out to be Oriental Bittersweet instead. This isn't necessarily intentional, but just shows that those selling it can't always tell the difference, either. Know your source!

Please visit our sponsors

  • Must have book: Pollinators of Native Plants

Where to buy native seed and plants ↓

Map of native plant purveyors in the upper midwest

  • Morning Sky Greenery - Native Prairie Plants
  • Minnesota Native Landscapes - Your Ecological Problem Solvers
  • Natural Shore Technologies - Using science to improve land and water
  • Itasca Ladyslipper Farm - Native orchids, container grown
  • Prairie Restorations - Bringing people together with the land

More photos

Photos by K. Chayka and Peter M. Dziuk taken at Long Lake Regional Park, Ramsey County. Photos courtesy Mark Wheeler taken at Oakdale Nature Preserve.

Comments

Have you seen this plant in Minnesota, or have any other comments about it?

Posted by: Mary K - Douglas County
on: 2016-10-28 08:50:01

Does Oriental Bittersweet leaves turn yellow in the fall? I may have American Bittersweet growing, but the leaves are very round with a pointed end. They have turned yellow for the fall.

Posted by: K. Chayka
on: 2016-10-28 09:13:51

I don't know what color leaves turn in fall, but do not use only the leaf shape to make an ID. Flowers or fruit will tell you for certain.

Post a comment

Note: All comments are moderated before posting to keep the riff-raff out. An email address is required, but will not be posted—it will only be used for information exchange between the 2 of us (if needed) and will never be given to a 3rd party without your express permission.

For info on subjects other than plant identification (gardening, invasive species control, edible plants, etc.), please check the links and invasive species pages for additional resources.



(required)




Note: Comments or information about plants outside of Minnesota and neighboring states may not be posted because Id like to keep the focus of this web site centered on Minnesota. Thanks for your understanding.