365 Urban Species. #160: Black Swallow-wort

[urbpan]

Location: Price Road, Allston.

Urban species #160: Black swallow-wort Cynanchum nigrum

Tiny star-shaped flowers , so dark purply-brown they look black, are the primary charm of this weed. Later in the season it develops pods that release seeds that float on silken parachutes (similar to, but more restrained than, cottonwood). It twines up chain-link, putting glossy dark green green foliage on ugly fences. Its attractiveness cause it to be introduced to North America as an ornamental. Unfortunately, there is little else that is positive about this plant, at least as it exists outside of its native range of Eastern Europe.

It is strongly invasive, and has several deleterious effects. Like other members of the milkweed family, it is poisonous. So when it crawls in among crops or pasture fields, it makes mechanical harvesting impossible, and whole pastures unusable by livestock. When it invades grasslands, there is a population drop among birds that nest in such areas. Monarch butterflies recognize it as a milkweed, and lay their eggs on it, but their larva are unable to feed on it, and starve. It joins garlic mustard and Japanese knotweed on the "least wanted" list, for New England native plants enthusiasts.

Comments

black swallowwort

[(Anonymous)]

I have this stuff invading my garden as well and share your frustration. How did the Ortho Brush-B-Gone work? I'll try anything to get rid of this stuff!!! Please help!!

Re: black swallowwort

[larksdream]

Yes, it does kill it. Although it can be hard not to spray nearby plants as well, depending on where it's growing-- I've heard some people use a glove or a brush to apply the Brush-B-Gone to the target plant.