About Vincetoxicum rossicum (Kleopow) Barbar.
Vincetoxicum rossicum is a flowering perennial herb in the family Apocynaceae, native to southern Europe, specifically Ukraine and southwestern European Russia. It was introduced to North America as an ornamental plant, where it is now considered highly invasive. It has become established across all of the Eastern United States, the midwestern United States, and southern Ontario and Quebec in Canada, and it is especially invasive in the Great Lakes Basin. It is commonly found growing alongside poison ivy. Its common names include swallowwort, pale swallowwort, and dog-strangling vine. Despite the name dog-strangling vine, it does not actually strangle dogs; however, dense patches of this plant can choke out native plants and small trees. There has been longstanding taxonomic confusion about this species' genus, with some authors placing it in Cynanchum and others in Vincetoxicum. Recent molecular and chemical analyses have confirmed it belongs to the genus Vincetoxicum. Vincetoxicum rossicum reproduces both via wind-dispersed seeds and vegetative growth. Its seeds are multiembryonic, which lets them colonize more area and gives the species a high reproductive rate. This species is a vine that grows best when it attaches to and climbs on other plants for support. Intermediate light is the optimal condition for its reproduction and growth; while the species can grow and reproduce under other light conditions, intermediate light produces the best growth results. It is typically found in dense vegetation, which supports its rapid growth enabled by its multiembryonic seeds.
