Vincetoxicum nigrum, a species in the family Apocynaceae, also known as blackswallow-wort, Louise's swallow-wort, or black dog-strangling vine, is a species of plant that is native to... Black and Pale Swallow-worts. Michigan Department of Natural Resources Michigan Natural Features Inventory 4/2012. BlackSwallow-wort has small purplish flowers, while Pale Swallow-wort has pinkish flowers. Both have long green pods and produce wind-borne seeds. Blackswallow-wort readily invades gardens, old fields, pastures, fence rows, wooded edges, riparian areas and roadsides. It grows in full sun and light shade. Means of spread and distribution. Blackswallow-wort develops vines from dense root crowns that grow three to four feet in height or in length on the ground. Blackswallowwort vine has been declared invasive in much of the Midwest and Northeast U.S. Check with your local extension office to find out if it is a problem in your area. Blackswallow-wort has dark purple, triangular petals about 1/8 in. long; pale swallow-wort has slightly longer, dull pink to burgundy petals. The meaning of BLACKSWALLOW-WORT is a European perennial twining herb (Cynanchum nigrum) that is occasionally cultivated and sometimes escaped in North America and has... For more information, check out the Black and Pale Swallow-worts page from SLEO PRISM.BlackSwallow-wort factsheet on Invasive Plant Atlas of the United States. Blackswallow-wort can spread long distances by seed and clones arising from root systems. Thick infestations in full sun can produce 2,000 seeds per square meter.
