Oriental bittersweet (Celastrus orbiculatus) is a climbing deciduous woody vine that thrives in disturbed habitats (e.g., roadsides, forest edges, riverbanks, etc.). This plant can grow rapidly, shading out and/or strangling native plants, including mature trees. In the fall and winter, after the leaves have fallen away from the bittersweet vines and the surrounding vegetation, the bright three-sectioned red-orange fruits and their yellow outer “husks” can draw your attention from quite a distance. As the capsules dry, they hinge open, revealing the inner fruit. It’s not hard to see why these attractive vines have often been used in seasonal wreaths and floral arrangements.

However, oriental bittersweet was imported from China, Japan and Korea in the late 1800s, and by the 1970s it had become widespread along the most of the U.S. Atlantic coast. The scale of problems that is causes have reached such a level that in 2009, the state of Massachusetts prohibited the importation, propagation or sale of this plant. Unfortunately, our local birds have not gotten this memo. Oriental bittersweet fruits are an often-consumed winter food for birds, such as American robins, black-capped chickadees, and European starlings, which then disperse the seeds in new locations with their droppings. Although it’s hard to explain the perils of propagating invasive plants to a robin, we as humans know better now. As lovely as the colorful fruits are, please avoid utilizing oriental bittersweet in wreaths or other decorations. Doing so only continues to spread the seeds and perpetuate the problem. 

If you find this plant on your property, it’s best to control it before it can establish a dense stand and wind its way up into the trees. For young vines, hand pulling can work, but be sure to get the entire root or it will resprout. For larger open areas, such as field, repeated mowing can be effective. But if you already have large vines growing up into trees, the vines can be cut close to the ground. Any dead vines that cannot easily be removed can be left to decay in the trees. In all cases, it’s best to carry out these activities before the plant has set seed, otherwise there’s a good chance you will dislodge many of the seeds in your eradication effort and you will be tackling quite the patch of bittersweet seedlings the following year. 

It is important to note that there is also a native species of bittersweet: American bittersweet (Celastrus scandens). American bittersweet can be distinguished from its invasive relative by its inflorescences (clusters of flowers, which later in the season form the berries), which form only at the terminal ends of branches, rather than at the joints (axils), as is the case with oriental bittersweet.