Look Out! Oriental Bittersweet

Not to be confused with American bittersweet, oriental bittersweet is a deciduous, woody vine that can grow up to 66 feet in length. Oriental bittersweet is an invasive plant which is becoming more and more abundant, while American bittersweet is becoming increasingly rarer.

Oriental bittersweet can grow almost anywhere and will try to kill any other vegetation around it, even mature trees. The Oriental bittersweet will snake its way up and around a tree to choke it out. Picture a plain white candy cane, this is your tree. Now picture the red stripe starting at the bottom and circling its way up, this is your Oriental bittersweet. Once this happens, the tree’s growth is inhibited and will eventually die. The weight of the Oriental bittersweet will uproot the tree and bring it to the ground during high wind events, snow storms, and ice storms and create what is called a blow over. Oriental bittersweet has created such a disruption in some forest ecosystems that it is even visible in areial photos.

Identification is easiest in the fall when the fruit capsules turn yellow. Many people will use these beautiful fruits in autumn wreaths and decorations. American bittersweet also produces beautiful fruits in the fall, but their fruit capsules are orange. This is the best way to tell them apart. Next fall if you go to pick seasonal bittersweet berries and the capsules are yellow please refrain from harvesting them because the seed bank stays viable for years so when one throws out a wreath with Oriental bittersweet on it, they are spreading the seeds.
If you are aware of locations with an Oriental bittersweet infestation please note the location and a photo (if possible) and send it along with your contact information to:

Courtney LeClair
Invasive Plant Education, Early Detection, and Mapping Specialist
WI Department of Natural Resources
101 S. Webster St.
Madison, WI 53707-7921
Phone: (608) 267-7438