: Oriental bittersweet, Asiatic bittersweet
: Invasive bittersweet hybridizes with American bittersweet, making it a genetic threat to the native species; may impact host species by reducing photosynthesis and girdling trees; the native bittersweet cannot be cut or transported without a bill of sale or proof of ownership under Michigan law.
: Deciduous; woody, twining vine.
: Simple, alternate, rounded, finely toothed, glossy, leaf tips acute or acuminate, 5-13 cm (2-5 in) long, turn yellow in fall.
: Light brown, often with noticeable lenticels; solid white pith; can climb 18 m (60 ft) high in trees and reach 10 cm (4 in) in diameter.
: Small, greenish yellow; five-petaled; clustered in leaf axils; blooms in May through June.
Fruit and seeds
: Outer skin (green in summer and yellow orange in fall) covers a red, fleshy aril, which contains 3-6 seeds; fruits clustered in leaf axils, colorful fruit often remains on vines through the winter.
: Native to Asia. Found in grasslands, open woods, woodland edges, undisturbed forests, roadsides and fence rows; extremely shade-tolerant.
: By prolific seed production and spreading underground roots that form new stems.
: Native American or climbing bittersweet (Celastrus scandens
) has elliptical rather than rounded leaves; flowers and fruits terminal rather than axillary.
Monitoring and rapid response
: Monitor open woods and edge habitats in late fall when most native plants have dropped their leaves. Invasive bittersweet has bright yellow leaves and female plants have persistent showy fruit in leaf axils. Begin control efforts in highest quality areas; cut plants, allow them to resprout and then spray with herbicide. Initiate control efforts before burning or opening up forest canopy as both may stimulate seed bank. In fire adapted communities, prescribed fire may top-kill vines.
: The Michigan Natural Features Inventory
(MNFI) has partnered with MISIN to provide the information in this fact sheet. Species images and/or information were used with permission from "A Field Identification Guide to Invasive Plants in Michigan's Natural Communities
" and "A Field Guide to Invasive Plants of Aquatic and Wetland Habitats for Michigan