Black dog-strangling vine, black swallowwort USDA PLANTS SYMBOL: CYLO11
Vincetoxicum nigrum Kartesz & Gandhi
Synonym(s): Louis' swallow-wort

Black swallowwort is an herbaceous, twinning, perennial vine. Leaves are opposite, dark green, oval, shiny, entire, 3-4 in. (7.6-10.2 cm) long and 2-3 in. (5.1-7.6 cm) wide. Flowering occurs in June to July, when dark purple, 5-petaled, star-shaped flowers appear in clusters. Flowers are approximately 0.25 in. (0.6 cm) across and covered with white hairs. Fruit are pods, similar to milkweed pods, which are slender, 2-3 in. (5.1-7.6 cm) long and split to reveal small seeds with tufts of white hair. The hair allows the seeds to be readily dispersed. Plants have rhizomes that sprout new plants. Black swallowwort invades upland areas with a wide range of light and moisture conditions. Black swallowwort is native to Europe and escaped from a botanical garden in Massachusetts.

Identification, Biology, Control and Management Resources