Art of Proprietation

Wednesday, October 15, 2008

Evil Weed

Have you seen this viney plant growing at the edges of mowed areas or sprouting in disturbed areas?

THIS IS EVIL WEED!!!

That's black swallow wart, an alien invasive from Spain / Italy that has taken root in the eastern United States over the last ten years.

This plant spreads by both rhizome and seed. It grows vigorously when in full sun, climbing and smothering other plants. And here and in the North East, it has no natural predator.

Black Swallow Wart is very difficult to destroy because of its vigor, ability to smother other plants and develop from cut roots.

Black Swallow Wart is in the same family as Milkweed, and has a similar toxin that discourages browsing animals from controlling it. Worse, it attracts native insects that do eat milkweed mistake it for milkweed and lay there eggs there, but the larva cannot survive eating Black Swallow Wart.


BSW has small dark flowers in July and develops seed pods in August. If those pods are allowed to mature, they will spread on the wind by the thousands.
Mowing the plants in late July helps to prevent the spread by seed, but it does not control the plant. It will spread by rhizome.
We are trying to control ours through weeding, smothering and cutting. We have not been at it long enough to know if we are having any success. I suspect that given the pervasiveness of this plant on our land, it will always be a problem for us that takes continual maintenance. But hopefully we can gain some control over it and recover some productivity of our land.

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4 Comments:

  • Ah, so that is the evil weed Christine was telling me about. Will the goats eat it? Is it toxic? If not then I suspect goats, sheep and pigs might be a solution to clearing it out of areas you can fence in. Our pigs love burdock, my bane, and thistles which I find beautiful but a thorn in my side. They'll also chew their way right though the large thorn blackberries.

    By Blogger Walter Jeffries, at 10:11 AM  

  • If the goats eat it, they certainly don't prefer it...

    I have read some places that it is mildly tixic, similiar to milkweed.

    If I leave the goats on it long enough, they do seem to harrass it a little, but not much, and not enough to control it.

    My current plan is to weed as much of it as I can after the goats move off an area. At least it is easy to see, as it is the last thing standing. I doubt I can erradicate it, but if I can knock it back some, that would be good.

    -mmp

    By Blogger MMP, at 4:44 PM  

  • Invasives are so hard to control, and most of the time go unnoticed until they are well established.

    Himalayan Blackberry is the culprit here. Not toxic in anyway, but the vines grow 20' per year. Very hard to control.

    It sounds like you are on top of your problem.

    By Blogger Throwback at Trapper Creek, at 8:48 PM  

  • I've been trying to figure out what this vine is for the last year. I was thinking it was in the kudzu family because it has the same characteristics. Thanks for giving it a name. My goats did actually eat it and no one seemed the worse for wear. I've been cutting it as lose to the ground as possible but some of the vines are already to the top of some of the trees. We moved here a year ago and I'm sure this has been establishing itself for a couple years now. As it gets taller and starts over taking the trees, it gets thorns on it. Very long and sharp. I hate this plant.

    By Blogger Danielle, at 1:13 PM  

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