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black swallow-wort

black swallow-wort (Vincetoxicum nigrum) [nonnative]
Photo © Leslie J. Mehrhoff, University of Connecticut,

Features and Behaviors

Black swallow-wort grows up to six and one-half feet in length. The leaves are paired and arranged opposite each other on the stem. Seedpods grow up to three and one-fourth inches in length. Flowers are positioned in the leaf axils and are dark purple to black in color.

Black swallow-wort flowers June through September. It may be found in the northern two-thirds of Illinois. This species is native to Europe. It is a vining milkweed that grows in a variety of habitats.

Illinois Range


​Kingdom: Plantae
Division: Magnoliophyta
Class: Magnoliopsida
Order: Gentianales
Family: Apocynaceae

Illinois Status: common, nonnative