Roundleaf bittersweet (Celastrus orbiculatus) is a large woody vine that was introduced in the 1860s. If left unchecked, infestations can overtake and choke out whole forests, with the vines sometimes growing as large as the trees that they grow on! 

The best way to tell the difference between the invasive and native American bittersweet is by looking at the fruits (see image above). Additionally, the native bittersweet rarely forms dense thickets like the non native species does. A good way to control large plants of roundleaf bittersweet is to cut the vine near the ground and apply an herbicide solution to the cut stump. Smaller vines can be brush cut or mowed (be sure to collect and dispose of the fruits!) in the winter, and the new leaves can be sprayed with herbicide in the spring.