Poison Ivy

Poison Ivy is well known for its irritant effects. The chemical urushiol activates an allergic response in most people that causes redness and swelling with an itchy feel. In extreme cases, it can even cause death if inhaled. Because it’s an oil, it can be washed off the skin with a strong enough soap and exposure to the chemical can have no reaction if caught fast enough. The chemical exists in the sap of the vine, and so is only released when the plant is damaged.

From an ecological standpoint, Poison Ivy acts as a parasite. It climbs trees and sends roots from the vine into the bark of the tree. Through this tactic, it steals water and nutrients from the tree it is climbing. It does provide berries that feed some wildlife, but the vine occupies a controversial status among naturalists. Its degree of irritation makes it reviled by anyone who has been exposed to it and its parasitic effects bring it no love among arborists. However, it is a native species to North America and does fill an ecological role.