The Devil’s Advocate of Poison Ivy

Poison Ivy isn’t evil.

I know, I know, that’s a controversial statement.

It’s like saying mosquitoes are good to have around. I want to be clear: I’m not saying this from the sidelines. I’ve had my share of encounters with its poisonous leaves!

The culprit of those annoying itchy rashes is an oil called urushiol. It’s found in the leaves, stems, and roots of poison ivy, oak, and sumac. Poison ivy has evolved to produce urushiol for good reason, and it’s actually very beneficial to our ecosystem!

Mammals such as deer, mice, rats, and even black bears munch on poison ivy leaves. A large variety of birds love to eat the white berries they produce in the fall. As a vine it often creeps along the ground or up trees and is perfect for smaller animals to use as shelter. If you were to take a walk along our trails, I guarantee that you’d see chipmunks or squirrels dashing in and out of the cover that poison ivy provides.

Surprisingly, primates like us and guinea pigs are the only animals to be affected by urushiol. Your dog could run through a patch carefree but, if you pet them… watch out for an itchy rash! So why would these plants evolve such a compound when primates aren’t even a threat to their survival? One theory is that urushiol may help heal wounds on the plant’s leaves that result from animal chewing. Another theory is that urushiol defends the plant from microbial pathogens.

I hope this helps you appreciate the value of poison ivy just a little. Be sure to visit Woodcock in fall and look for the brilliant red leaves that this fascinating plant flaunts in autumn… just be sure to keep your distance.

Kevin Andros has been an educator at Woodcock for over five years and teaches numerous field trips, after school programs and is director of first aid at summer camp. Kevin especially loves reptiles and fungi.