Black swallow-wort (Vincetoxicum nigrum) is actually part of the milkweed family. Monarch butterflies, whose only "host" plant is milkweed, can lay their eggs on the black swallow wort thinking it's suitable but it's toxic to the larvae and then they die. (Milkweed is the ONLY food monarch caterpillars can eat.) We can't let that happen. Also, it will totally take over your yard and spread to all your neighbors! Get it by the roots and toss it in the garbage—not yard waste or compost those roots