Eastern Asia, Korea, China and Japan (NPS)
Plant: deciduous, woody, twining vine, sometimes occurring as a trailing shrub; stems of older plants can reach 4 in. in diameter. Abundant clusters of small greenish flowers emerge from most leaf axils; globular, green to yellow fruits split open at maturity to reveal fleshy red-orange arils that cover the seeds; seeds germinate in late spring.
Leaves: alternate, glossy and rounded with finely toothed margins.
Spreads: by seed, which is dispersed to new areas by many species of birds and by people who are not responsible when disposing of faded bittersweet wreaths and other floral decorations; it expands locally by stolons and rhizomes and through root suckering (the ability to send shoots up from the roots).
Look-alikes: is easily confused with the native American bittersweet (Celastrus scandens), which produces flowers just at the terminal ends (stem tips) rather than from multiple leaf axils as in the exotic invasive. For this reason, it is important to correctly identify the vine before controls are attempted.
(NPS)
Oriental bittersweet was introduced into the United States in the 1860s as an ornamental plant and it is still widely sold for landscaping despite its invasive qualities.