SafePlants

Oriental Bittersweet (Celastrus orbiculatus)

Celastrus orbiculatus, commonly known as Oriental bittersweet, is a woody, perennial vine recognized for its invasive nature in many regions.

Considerations for Pets

• The text mentions that birds and small mammals feed on the fruits of Oriental bittersweet. While this doesn't explicitly state toxicity, it's important to monitor pets if they ingest the berries, especially in large quantities.

Taxonomy and Nomenclature

• Scientific Name: Celastrus orbiculatus Thunb.
• Common Names: Oriental Bittersweet, Chinese Bittersweet, Japanese Bittersweet, Asian Bittersweet, Asiatic Bittersweet, Round-leaved Bittersweet
• Family: Celastraceae (Staff-tree family)
• Synonyms: C. articulatus

Distribution and Habitat

• Native to Eastern Asia, specifically China, Korea, and Japan.
• Introduced to North America in 1860 and now grows in much of the eastern United States.
• Found primarily along forest edges, roadsides, and meadows.
• Oriental bittersweet has also naturalized in eastern North America.

Ecological Role

• Classified as an invasive species.
• Poses a serious threat to native ecosystems by crowding out native species.
• Aggressively twines around and grows over other vegetation, causing damage or death due to lack of sunlight.
• Can girdle and break trees and shade and smother vegetation.

Morphological Characteristics and Growth Habits

• Deciduous, twining vine.
• Rapidly spreading.
• Alternate, round, glossy leaves.
• Reaches a maximum height of up to 19 m (60 ft).
• Younger leaves are oblong, but mature leaves are more rounded.
• Flowers are found in leaf axils.
• Ripening fruits first turn yellow in late summer and are fully ripe later.

Distinguishing from American Bittersweet

• Oriental bittersweet closely resembles American bittersweet (Celastrus scandens).
• A key difference is that American bittersweet flowers and fruits are only found at the terminal ends of stems, whereas Oriental bittersweet flowers and fruits are found all along the stem at leaf axils.
• On American bittersweet, the berries are clustered at the end of the stem, rather than spread out along the length of the vine as in Oriental bittersweet.

Interactions with Other Organisms

• The introduction of Oriental bittersweet to non-infested areas is often associated with birds and small mammals feeding on the fruits and dispersing the seeds.
• Birdwatchers appreciate bittersweet berries as a food source for birds in the winter, including Eastern bluebirds.

Additional Resources

• USDA’s National Invasive Species Information Center
• RHS (Royal Horticultural Society)
• Dave's Garden