Terrestrial invasive species

Nature

Most of these invasive plant factsheets are created from the booklet Minnesota invasive non-native terrestrial plants, an identification guide for resource managers.

Check the additional resources and herbicides table for more information.


Oriental Bittersweet (Celastrus orbiculatus)


 

Description:

Appearance: Deciduous vine that grows up to 66 ft. long. Vines climb by winding around a tree or other support structure.

Leaves: Alternate, simple, vary in shape from oblong to almost round. Leaf size is also variable from 2-5" long to 1.4-2" wide. Leaf margins have rounded teeth.

Flowers: There are separate male and female plants. Flowering occurs in the spring and flowers are arranged in clusters of 2-7 at the leaf axils. Each flower has 5 petals and 5 sepals. Flowers are small and greenish-yellow.

Fruit: Fruits are round and change in color from green to bright red with a yellow capsule as they mature. Typical female plants can produce up to 370 fruits which ripen in the fall.

Roots: Underground rhizomes spread and can send up new plants.

To distinguish from the native vine, American bittersweet (Celastrus scandens):

  • American bittersweet has orange capsules around red fruits, Oriental bittersweet has yellow capsules around red fruits.
  • American bittersweet flowers and fruits are only found at the terminal ends of stems, Oriental bittersweet flowers and fruits are found all along the stem at leaf axils.
  • Leaf shape is highly variable and not a good characteristic for distinguishing American vs. Oriental bittersweet.
  • See MDA website for photos comparing the two species.
  • Additional resources for distinguishing American and Oriental bittersweet:

Ecological Threat:

  • Highly invasive in forests in the Eastern US. Vines girdle trees as they climb to dominate the canopy and shade the understory, reducing and preventing the growth of other plant species. Oriental bittersweet still has a limited distribution in Minnesota at this time. By detecting Oriental bittersweet populations early and rapidly treating infestations in Minnesota, we may be able reduce the impact this species has in Minnesota.
  • At times, the weight of Oriental bittersweet vines in the canopy can break trees, especially with the additional weight of snow and ice.
  • Oriental bittersweet outcompetes and displaces American bittersweet (which is native to Minnesota) to the point that Connecticut now lists the formerly common American bittersweet as a species of concern. Additionally, by hybridizing with American bittersweet, Oriental bittersweet causes further loss of American bittersweet populations.
  • Oriental bittersweet is a MDA Prohibited Noxious Weed (Eradicate List) in Minnesota meaning that above and below ground parts of the plant must be destroyed.  Additionally no transportation, propagation, or sale of Oriental bittersweet and its cultivars (including 'Diana', 'Hercules', 'Indian Mix', 'Indian Brave', and 'Indian Maiden') is allowed. Report Oriental bittersweet by emailing "Arrest the Pest" arrest.the.pest@state.mn.us or calling 651-201-6684 (metro) or 1-888-545-6684 (toll-free)

 

Control Methods:

Prevention:
Oriental bittersweet has a limited distribution within Minnesota so there is still a chance to prevent it from spreading throughout the state. People move seed by using fruiting stems in flower arrangements. Oriental bittersweet is sometimes mistakenly labeled as American bittersweet then sold and planted. Avoid planting Oriental bittersweet.

Mechanical:
For small populations, pull or dig up plants. Regular, weekly mowing will control Oriental bittersweet, but less frequent mowing may result in suckering from the roots

Chemical:
Cut stems and apply herbicide (such as glyphosate or triclopyr) to the cut stem.

Native Substitutes:

Additional resources: