Black Swallow-wort, Dog-strangling Vine, Louis' Swallow-wort

People,

*Please don't cultivate this plant.* It's invasive, very difficult to eradicate, and it kills butterflies that mi...Read Morestake it for the more beneficial milkweed. It will choke out everything else in your garden and spread, through its floating seedpods, all around your neighborhood.

http://en.wikipedia.org/wiki/Cynanchum_louiseae

I originally found this plant growing in a sidewalk crack. The glossy leaves and black flowers looked interesting, so I snatched a seed ...Read Morepod and raised some seedlings. At the time I was gardening in sandy loam with a lot of shade, where this plant stayed small and grew 2-3 feet up the fence. My new house, where I still live, has heavy clay soil and lots of sun -- where the black swallowwort quickly turned into a monster. Besides filling the air with billions of seeds, which germinate immediately as soon as they land, it also spreads via underground stems. The waxy leaves repel all herbicides and any little bit of root left in the ground will quickly turn into a new clump.

A local specialty nursery used to sell this plant because it is apparently the food source for a particular butterfly and the nursery's owner was really into butterflies (they no longer sell it). Unfortunately, when this plant was brought over from Europe they forgot to bring along the butterfly that eats it. the foliage, when bruised or crushed, smells horrible -- worse than Tree-Of-Heaven (Ailanthus). This plant should be the poster child for noxious weeds.

This is an absolutely TERRIBLE INVASIVE WEED. It will grow quickly up and engulf adjoining plants in your garden, entwining its single c...Read Moreentral stem and climbing other plant stems and foliage and jumping from plant to plant.
As it gets larger it produces many pepper-like seed pods that are heavy enough to weigh down other plants. The very tiny near-black precursor flowers are virtually unnoticeable having no aesthetic value whatsoever. It will spread from the garden to the lawn where mowing will not eliminate it.

It is extremely invasive and practically impossible to eliminate. Its central stem is attached to a spider weblike root system made up of hundreds of radiating and branching white roots. Even the smallest of plants cannot be pulled because the roots concretely anchor it to the soil and the stem breaks off. Days later it re-grows. It MUST BE dug out, and then it is not likely that all of its tiny fragile rootlets will be removed. Spraying it with Roundup will temporarily brown up the leaves but not kill the root system. I've had some success killing it but cutting the stem just above the ground and spraying the herbicide on the cut end of the stem, a method recommended by a nurseryman. Short of this time consuming and frustrating process, the garden must be constantly inspected for signs of the plant, and pulling it before it entangles itself with your desirable plants and produces seed pods.

Beware if it ever gets into your garden, or a neighbor's!!!

This is probably THE WORST WEED I have on my acre...and that's saying alot because I also have poison ivy and bittersweet vine. It grows...Read More about 2-3 feet tall, twining around itself so you can't walk through it, hence one of its many nicknames 'dog strangle weed'. It makes winged seeds that the wind blows around. Roots are hard to get out IF the ground is dry. I'm trying to eradicate it by pulling it up by hand when the ground is moist but we're talking 1 plant/3 inches, BEFORE it goes to seed. You there in Seattle, who is growing it on purpose - HUGE MISTAKE! imho.

I hate this vine! It's taken over my yard and is trying to work it's way to my gardens. Round up for poison ivy works wonders!

Extremely aggressive and extremely foul-smelling vine that can grow anywhere. It can strangle trees and shrubs with ease if given the ch...Read Moreance. It smells like a dirty rabbit hutch or guinea pig cage. The smell gives me a headache. Although the dark green foliage can be attractive, I recommend killing this vine. Cut the stems close to the ground and dip the freshly wounded main stems in RoundUp concentrate.

This is consider an invasive species in North America and acts as an attractive for Monarch butterflies to lay their eggs on it. The larv...Read Moreaes have a high death rate as the plants don't have the chemicals that the larvaes need for defense and also larvaes starves to death because swallow wort don't have the right kind of nutrients for them. This vine is currently the most common around New England, most of the Great Lakes area west to Wisconsin.

This is a very interesting vine, I must say. So far, I have had a positive experience with it. How I acquired the plant is actually fairl...Read Morey funky. When I lived in Seattle, I was the landscape manager for a large and well known nursery. One day, the crew came back with this plant stuffed into a pot. They saved it as none of us had ever seen it before.

It had been growing in the middle of a patch of low growing Juniper! Obviously a very tough plant! I saved the plant for about a year or so in our company grow lot, in just a 5 gallon black plastic generic pot. I eventually moved back to my native state of Montana and brought this plant with me among countless others. I thought it would for sure die in our cold Winter climate as I had left it outside as an experiment. Well, surprise.....it sprouted right back in Spring, even though it looked like it had croaked. Funny, because in Seattle it stayed evergreen all year. Now that I have planted it in a bed near my home in Montana, it behaves as a deciduous perennial vine and has totally tripled in size now that it is out of its pot and has lots of room for its roots.

I find it to be a beautiful vine, with its tiny star shaped black-mauve flowers that really stink if you smell them, although the hover-flies, regular flies and some bees really love this plant! I've seen other VERY odd insects on it as well. It is definitely an insect attracting plant. The glossy leaves are also quite attractive. Mine is now well established and it produces milk-weed like pods in fall. They are full of cottony seeds and lately I'm noticing baby Black Swallow-worts in some odd places around my house and property. I hope I didn't create a weed. Doh! I've done it before...........but only by accident. Anyway, if you're looking for a vine that will grow fairly tall given support; grows fast and has very attractive leaves and tiny clusters of beautiful blacky-mauve coloured flowers, this vine might be a good choice. At least in an area where it doesn't have the potential to become weedy and crowd out any natives. Sorry this was so long!

Other names I have learned for this vine are: Vincetoxicum Nigrum, Cynanchum and "Dog Strangling Vine"........which I just can't seem to picture in my mind nor do I want to. - Cheers - MontanaVineMan