Planet Poison Ivy

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Vacant Factory, photo by Voxphoto.

I was driving the other day and noticing that the ivy seems especially profuse this summer. I was ready to chalk it up solely to the warm, wet summer of 2010 when my daughter Kenyon told me about this interview of Dr. Lewis Ziska, plant physiologist for the U.S. Department of Agriculture’s Agricultural Research Service by Michele Norris on NPR:

NORRIS: We’ve long known that poison ivy is nasty stuff. Even if you barely brush up against it, you can get an angry, weeping, contagious, red rash that takes weeks to heal. Well, it turns out that poison ivy, along with its voracious cousins poison oak and poison sumac, is even more of a nuisance this summer. The plants are spreading faster, growing larger, showing up in new places and becoming more toxic. It’s the kind of thing that’s so scary, it almost deserves its own soundtrack.

…NORRIS: Why is the plant spreading more and becoming more voracious? Why is it growing larger?

Dr. ZISKA: One of the things that we think is occurring is that as carbon dioxide is increasing in the atmosphere – carbon dioxide, as everyone knows, is a basic greenhouse gas, but it’s also plant food. And plants take that carbon, and they convert it into sugars and carbohydrates and so forth.

But not all plants respond the same way to that resource, and we think that vines, particularly vines like poison ivy or kudzu or other noxious weeds, seem to show a much stronger response to the change in CO2 than other plant species. So on average, the poison ivy plant of, say, 1901, can grow up to 50 to 60 percent larger as of 2010 just from the change in CO2 alone, all other things being equal.

And as a result of that change, we see not only more growth but also a more virulent form of the oil within poison ivy. The oil is called urushiol, and it’s that oil that causes that causes that rash to occur on your skin when you come into contact with it. Read on >

Check this out bigger and in in Ross’s A Few in Color slideshow and know your poison ivy!