|Black dog-strangling vine, black swallowwort
USDA PLANTS Symbol: CYLO11
USDA ARS GRIN: 405616
|Vincetoxicum nigrum (L.) Moench
Taxonomic Rank: Magnoliopsida: Gentianales: Asclepiadaceae
|Synonym(s): Louis' swallow-wort
- Cynanchum louiseae is an herbaceous, twining, unbranched, perennial vine which can grow up to 6.5 ft. (2 m) in length.
- Leaves are opposite, dark green, oval, and shiny with entire margins. Leaves are from 3-4 in. (7.6-10.2 cm) long and 2-3 in. (5.1-7.6 cm) wide. A short petiole attaches the leaf to the vine.
- Clusters of 6-10 flowers bloom from June to September. Five lobed dark purple corollas are approximately 0.25 in. (0.6 cm) across and covered with short white hairs on the upper surface.
- 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 hairs. The hairs allow the seeds to be readily dispersed by wind. Plants have rhizomes that sprout new plants.
- Ecological Threat
- Cynanchum louiseae readily invades upland areas. It tolerates a wide range of light and moisture conditions and can be found invading a wide variety of upland habitat types. It is native to Europe. The history of its introduction is uncertain, but it may have escaped from a botanical garden.