Oriental Bittersweet (Celastrus orbiculatus) Celastraceae (Staff Tree Family) Eastern Asia, Korea, China and Japan
Introduced 1860s as ornamental Disturbed Areas Woodland Edges Coastal Areas National Park Service PCA Alien Plant Working Group
Woody Vine Growth Habit = Ecological Threat “Strangle Weed” Climbs over vegetation (including canopy trees) Causes vegetative death from overshading Can cause uprooting /blow over by excessive weight Outcompeting the native bittersweet, C. scandens
Prolific Seeding Female (fruiting) and Male (non fruiting) plants
Alternate Leafing/Axillary Flower Buds Small greenish flowers born on axillary (mostly leaf) clusters Native Bittersweet (C. scandens) has Flowers on Terminal Buds
C. Orbiculatus Leaves nearly as wide as they are long Alternate (Native Honeysuckles are opposite leaved) Glossy and finely toothed margins
CONTROL Part I Treat as Woody Invasive Cut Stem and treat with herbicide (triclopyr / glyphosate concentrate) Before fruiting (seeds germinate late spring) Winter work
CONTROL Part II Fall Applications of foliar spray (such as Garlon 3A) Mini Cut Stump Treatment AND/OR Cut down patches now, and come back in 30 days w. foliar app to resprouts Timing and care to avoid native groundcover.
Native v. Invasive Invasive C. orbiculatus Flowers and Berries on leaf axils Native C. scandens Fruits and Flowers on Ends Less Prolific Fruiting C. scandens
Not a Good Thing Scrambling, sprawling, bees, poison ivy, etc. Be sure to do your follow up treatments or all that suffering goes to waste. Rebecca Grill Natural Areas Manger Park District of Highland Park rgrill@pdhp.org