Last weekend I noticed the orange berries of Oriental Bittersweet are everywhere, beside roads, in yards and in the treetops.
I learnt about Oriental Bittersweet at a presentation by Barbara Bravo called ”Invasive Plants in the Hudson Valley”. (An ‘invasive’ is a plant or tree that is not indigenous to the US that adversely affects the natural environment).
There are two types of Bittersweet vine in the US; the Oriental Bittersweet (Celastrus orbiculata) which was introduced in the 1860s from China, Japan and Korea and the American Bittersweet (Celastrus scandens).
Oriental Bittersweet is an invasive vine growing 66′ tall which crowds out other plants and trees, including American Bittersweet. The woody vine wraps around trees and kills them, while the weight of the vine can smother and topple mature trees. It is more vigorous than the American Bittersweet and spreads by underground roots and from berries which are eaten and dispersed by birds and mammals.
Oriental Bittersweet can be removed by cutting back the vines and digging up the roots. Or a systemic herbicide can be used (glyphosate or triclopyr); cut the stem about 1″ above the ground and apply the herbicide to the stem, always follow directions on the label. Make sure no berries are left behind and burn or dispose of them in the trash.
American Bittersweet is rare in the wild but is available from nurseries. It grows 30′ high. Identification; the leaves have a pointed tip, the berries are a darker red and are in clusters at the ends of stems that extend beyond the leaves. For advice and help identifying American Bittersweet, contact your local Cornell Cooperative Extension.
Sources of American Bittersweet vines: