A very serious problem in the Finger Lakes region, along with the similar species C.rossicum. Seed pods are superficially similar to the native Asclepias spp. pods, with silky tassels to aid distribution. Hike upper Taughannock to see the ground covering stands of Cynanchum spp. Black swallowwort is prohibited in New York; it is illegal to purchase, sell, transport or propagate.