Ask around, and you’ll probably hear about someone who unknowingly yanked poison ivy (
Toxicodendron radicans
) out of their yard and itched for days.
“Poison ivy is an insidious invader,” says Ed Hedborn, plant records manager at The Morton Arboretum. “It will show up in the middle of your lawn, under trees and on your fence. You’ll find it crawling up your clothes line or mixed in with clematis on your trellis.”
Some poison ivy leaflets are as big as your face. Others, just a few inches. They can be mitten-shaped or not. Some have serrated edges. Others don’t. Some have hairs only on the undersides, or all over, or nowhere. Get the picture?
“It’s not even true that poison ivy has a red stem. It can appear red in spring, but the color fades in summer,” says Hedborn, who once donned head-to-toe protective gear to wade in a huge thicket of the stuff. “I’ve seen it growing as a ground cover, as a small upright shrub, and I have seen it acting like a tall shrub, with stems two to three inches in diameter and up to eight feet tall!”
Here’s what you can count on, according to Hedborn: a poison ivy leaf consists of three pointy leaflets on a stem. The stems connect to the plant in an alternate pattern: left, right, left. Soon, poison ivy will be one of the first plants to turn color, transforming into a vivid scarlet. You may also see 1/8-inch diameter ivory or yellow-white fruits.
About eight in 10 people get an itchy skin reaction within a day or two of touching poison ivy. If you handle any part of it — leaves, stems, roots — immediately rinse skin under cool running water for 15 minutes.
For free advice about ways of removing poison ivy, contact The Morton Arboretum Plant Clinic at
plantclinic@mortonarb.org
, 630-719-2424, or
mortonarb.org/plantadvice
.
Laurie Casey writes for The Morton Arboretum in Lisle.
