Asiatic Bittersweet, a menace!

Do you remember gathering this vine for decorative use? It has not been too many years ago that a lot of us looked forward to gathering this vine in the fall and adding it to our arrangements and fall wreaths. Beautiful, we thought!

Well, let me tell you about this “beautiful” berry-filled vine! It’s a nightmare and we have it in many areas in Castine. It is invasive and has done much damage. Because it is a serious threat to other species and to whole habitats, the University of Maine Cooperative Extension and other organizations have published information about the Asiatic Bittersweet (Celastrus orbiculata). For information from the UMaine Extension Service, go to their website (http://www.umext.maine.edu) and search for “invasive plants.” From there you can order a bulletin on invasive plants, download a “PDF” file or view a web page (html).

Probably brought in from East Asia around the mid 1800’s, its use was for ornamental purposes. Before being discovered as a menace, oriental bittersweet was planted as highway decoration in many states. As with a lot of non-native plants, ornamental bittersweet goes rampant with nothing to keep it in check. Birds disperse the seeds plus the plant itself has a high reproductive rate, long range dispersal mechanisms and the ability to root sucker.

Asiatic bittersweet is similar in appearance to the native species American bittersweet. However, Asiatic bittersweet is distinguished from American bittersweet by the fact that its fruit and flowers are located in clusters of three to seven between the leaf and the stem. American bittersweet's fruit and flowers are located at the branch tips only.

Okay, you find it on your property, what do you do to rid it from your property? It takes tenacity! The UMaine Extension recommends the following for control: “Small patches can be hand-pulled. Take care to remove the entire root to prevent resprouting. Low patches have been successively removed by cutting the vine and treating the regrowth with a triclopyr herbicide. Control is more successful in taller patches when cut stems are immediately painted with triclopyr or glyphosate (Roundup, for one). This plant has a substantial seed bank, and complete eradication may depend on repeating control methods for several years.”

The vine is at its most easily identified during the fall season. If you cut the vines, remember: do not put them in your compost or brush piles. The prolific seed pods ensure its return—hundred fold!

Submitted by: Nancy Watson, Communications, Castine Garden Club