Fact Sheet

Oriental Bittersweet


Celastrus orbiculatus

What is Oriental bittersweet?

Plant Type: perennial deciduous woody vine

Family: Celastraceae (bittersweet)

Form/Size: rapidly spreading, twining, woody vine (occasionally trailing shrub), can climb to heights greater than 18m

Leaves: simple, alternate, rounded, slightly toothed

Flowers: in clusters, greenish-yellow, very small, 5 petals, in leaf axils, blooms in spring to early summer

Fruit: globular berries, turning from green to bright yellow, which at maturity split open to reveal 3 red arils (specialized growths that cover seeds), each containing a seed
Note: only female plants bear fruit

Means of Spread: prolific sexual reproduction by seed, mainly dispersed by birds, but also by humans (folk art and crafts); vegetative reproduction by root suckering and suckering of cut stumps

Other Features: outer surface of roots is typically bright orange

Similar Native Species: none in NS; may be confused with American bittersweet (Celastrus scandens) from southern SK to NB (probably extirpated from NB), and in the US; flowers and fruits occur in terminal clusters on the native bittersweet; leaves are twice as long as they are wide, and tapered at both ends on the native bittersweet

Where did Oriental bittersweet come from?

Origin: Asia (Japan, China, Korea)

North American Introduction: around 1860

Reason: ornamental plant

Where am I likely to find Oriental bittersweet?

Habitat Type: forests, forest edges, fencerows, fields, old homesteads, gardens, coastal areas, and salt marsh edges; seedlings can establish in dense shade

Distribution in NS: Annapolis Valley

Non-native Distribution: NB, NS, ON, QC and US States AR, CT, DC, DE, GA, IA, IL, IN, KY, MA, MD, ME, MI, NC, NH, NJ, NY, OH, PA, RI, SC, TN, VA, VT, WI, WV (USDA Plants Database)

Why is Oriental bittersweet a problem?

Environment: can germinate in full shade, rapid growth; overruns natural vegetation; strangles shrubs and small trees, weakens large trees; shade created by this vine may inhibit the germination of other species

Economy: no information; possible impacts to forest industry

Oriental Bittersweet
Oriental Bittersweet leaf
Oriental Bittersweet berry

Stewardship Actions

What should I do if I find Oriental bittersweet?

Report: report the observation to ISANS www.invasivespeciesns.ca

Control: frequent mowing (weekly) will discourage growth; hand-pull small plants; vines climbing into trees should be cut at 1-2m height, and at ground level; cut stumps will sucker prolifically; suckers can be eliminated with foliar applications of triclopyr-based herbicide; foliar applications of glyphosate-based herbicides have been ineffective in killing roots; long-term commitment required to deplete seedbank
Note: it is illegal to use a pesticide in any way that is not specified on the product label

Disposal: limited information; proper disposal of seeds and root fragments is important to prevent new infestations; dry and burn on site, or dry and bag in heavy duty black plastic; do not compost