Large Oriental Bittersweet Vines Can Be Killed by Cutting Alone: Implications for Utility Arboriculture and Other Hazard Tree Work

Oriental bittersweet (Celastrus orbiculatus) is an invasive, exotic, woody vine introduced to North America in the mid- to late 1800s from East Asia. This vine is problematic because it can kill trees through competition and mechanical stress, which in turn creates problems for tree care professionals in utility right-of-way and other hazard tree work. Oriental bittersweet is becoming more prevalent as a problem throughout the eastern United States. Two manipulative field experiments were conducted across the Hudson Valley in New York State to test the timing of cutting and glyphosate herbicide effects on large vine mortality. While results from the first year indicated that herbicides were needed with vine cutting to achieve high mortality rates, this was not true with second year results. Cutting vines without herbicides produce the same, high rate of mortality of oriental bittersweet vines after the second year (>90% kill) as cut-stump treatments with herbicides. It may be important that high kill of cut vines is related to large vine size, and that stumps were in forest shade. Herbicides may not be necessary to kill cut-stump methods to kill oriental bittersweet vines that have a minimum stem diameter >2–3 cm and are growing in areas where stumps are in shade.