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The Monday Garden
Enhanced Species: Poison Ivy

Issue No. 0074 - August 24, 2003
by Sue Sweeney

Poison Ivy (rhus radicans) (Cashew family).  Bad stuff [for humans].  Here it is in a privet hedge down the street from me, blissful because it's being ignored by the humans who created an environment where it could thrive.
In eco-lingo (the talk of ecologists, conservationists, and the like), the word  "invasive" is usually linked with "alien".  That's so because, generally, it's things from outside the ecosystem that run riot, given half a chance, destroying bio-diversity.

There are, however, some native species that are as much a problem, from humans' perspective, as the worst invasive alien.  These are problems of our own making, such as a yard full of Canadian geese guano.  The eco-lingo is "enhanced", meaning a species that flourishes around humans.  Good examples are the cockroach and the house cat. 

Two notorious North American noxious weeds for which we only have ourselves to blame are ragweed and poison ivy.  Both flourish where humans have replaced the native forest and meadows with fencerows and roadsides, and have left patches of raw earth.

How it happens: the birds find the white poison ivy berries good eating.  As a result, the non-digestible seeds end up, nicely fertilized with bird droppings, under the birds' roosting places.  This works for the birds and the poison ivy.   In the deep shade of the forest, poison ivy seedlings don't crowd out other plants, which works for the eco-system.  However, give too many seedlings a (human-made) place in the sun, and they'll take over.   This works for the birds and the poison ivy but not for the rest of us. 

When I was a kid, humans balanced out their poison-ivy-enhancing behavior by pulling the plant up anywhere it was found.  However, today, I see poison ivy all over suburbia.  If you have trouble identifying it in the summer, wait until mid fall and look for the brilliant red leaves, often smothering trees.  Some conservationists who would gladly eradicate the alien invasive vines such as porcelain vine (issue 31, 10/27/02), Indian bitter sweet (issue 40,12/29/02), and rosa multiflora (issue 44, 01/26/03), think we ought to leave the poison ivy because it's native and the birds eat it.

That doesn't do it for me.  I hear that poison ivy got so far out of hand on Fire Island, for example, that some of the wild area have been abandoned by all but some (very fat) birds.  Remember that poison ivy is very dangerous to humans.  The only way to give rid of an acre-size patch is to bring bulldozers and workers in "moon suits".   But then what would you do with the dead stuff that still contains the deadly oils?  You can't even burn it except under controlled conditions because the smoke carries the oil and is very harmful to touch or breathe.

The best thing to do for poison ivy is pull it up when it's small.   Do as the "pooper -scoopers" do: use a couple of layers of plastic shopping bag as an oversized glove to protect your hand while pulling up the plant. Then reverse the bag to cover the plant; tie and drop in the garbage.  Cut large vines at the root, dig up and destroy the root (place in sealed black garage bag in the sun for a few months).   Consider leaving the vine to die in place; don't try to pull down a large vine without protection, particularly for the face and eyes.

BTW: don't think you're immunity to poison ivy just because it hasn't bothered you in the past.  Only too many people have ended up in the hospital this way.  And don't think it's just a minor skin rash.  A big does of poison ivy can lead to serious, long-term health problems.

Further information on poison ivy and its kin poison oak and poison sumac: http://poisonivy.aesir.com/view/welcome.html

From The Monday Garden. Copyright © by Sue Sweeney. Reproduced with permission. 

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