Large Oriental Bittersweet Vines Can be Killed by Cutting Alone

9880941632014PDFTech ReportSPR Research Project No. C-06-24Invasive plantsHerbicidesVegetation controlRoadside floraField testsRoadside floraInvasive plantsmaintenanceUnited StatesNew YorkNew York (State). Dept. of TransportationNowak, Christopher A.Peck, Caryl J.State University of New York. College of Environmental Science and ForestryNew York (State). Dept. of TransportationUnited States. Federal Highway AdministrationUS Transportation CollectionOriental bittersweet (Celastrus orbiculatus Thunb.) is an invasive, exotic, woody vine introduced to North America in the mid- to late 1800s from East Asia. The New York State Department of Transportation considers oriental bittersweet a problem because it can kill roadside trees through competition and mechanical stress. These hazardous and dangerous trees then need to be removed before they cause harm. Two manipulative field experiments were conducted across the Hudson Valley by the State University of New York College of Environmental Science and Forestry to test timing of cutting and glyphosate herbicide concentration effects on large vine mortality. While results from the first year indicated that herbicides were needed 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 rates of cut vines is related to the large vine size and that stumps were in forest shade. We concluded that it may not be necessary to apply herbicide via cut stump methods to kill oriental bittersweet vines that have a minimum stem diameter > 1-inch and are growing in areas were the invaded trees and forest systems are not significantly disturbed with vine treatment