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Poison Ivy, a ‘Familiar Stranger’ that could ruin your summer

Microbiologist John Jelesko has learned not to take any chances when he touches poison ivy. (Courtesy of John Jelesko)

It was a close encounter in 2012 that made microbiologist John Jelesko take an interest in poison ivy.

The Virginia Tech associate professor was cutting up a downed tree with an electric chainsaw. What he didn’t realize was that his power cable had been dragging through poison ivy. So, at the end of the day, as he coiled the cord around his palm and elbow, he inadvertently launched a career-bending science experiment.

“Within 48 hours, I had your classic case of poison ivy on my arm. And as a scientist, I said, ‘This is interesting, how bad can it be? I’ll just leave this untreated,’” he recalled, sheepishly. “In about two weeks, I had learned just how uncomfortable poison ivy rash could be.”

Uncomfortable sounds like an understatement. Jelesko said he barely slept while fighting the urge to “claw my itching flesh off.” Eventually, he went to his family doctor, who prescribed oral steroids.

The experience sparked years of research into a plant he calls a “familiar stranger.” He has studied the chemical, urushiol, that triggers that telltale rash and the plant’s biology overall.

The tricky thing about avoiding poison ivy, Jelesko said, is the plant is highly adaptable and can take many different forms in different environments.

“It’s remarkable,” he said, with a laugh. “There’s just an enormous amount of things with this plant that are currently unknown.”

Here, he offers insights into how to recognize Toxicodendron radicans, the scientific name of the plant, before you risk touching it — and what to do if it’s too late.

Know The Leaf Shapes

The axiom “leaves of three, let it be” is accurate, said Jelesko, but those leaves can come in many shapes, even on the same plant. You’re safe if the plant has thorns — poison ivy doesn’t — but it does sometimes have little white berries.

Can You Recognize This Leaf?

All of these are the same pesky, rash-inducing plant. Poison ivy leaves sometimes appear with jagged or lobed edges, and sometimes smooth.

Same Plant, Many Forms

Poison ivy can present as a vine or a shrub. When mature vines climb up a tree, their shape can even mimic that of the host tree. Simply pushing aside an innocent-seeming branch could make the passer-by pay a few days later, when a rash begins to well up.

Jelesko’s latest research, which is not yet published, finds that in cities poison ivy tends to grow as a climbing vine, whereas out in the forest, most of the plants are ground-creeping vines. And poison ivy is much more prevalent in “landscapes modified by humans” than out in the middle of the woods.

Some poison ivy vines can be downright awe-inspiring in their size, like the one in this video.

What To Do When The Tricky Plant Wins …

If you think you’ve touched a plant, or unfortunately know you have, follow these tips to alleviate the problem. Of course, prevention is the best route. For John Jelesko, he now dons a protective Tyvek suit and two pairs of gloves when he wallows in poison ivy. Your last line of defense:

Photo Cover: Microbiologist John Jelesko has learned not to take any chances when he touches poison ivy. (Courtesy of John Jelesko)
Photo #2: (Clockwise from top left) Poison ivy with smooth edges; jagged edges; round leaves; notched leaves. All pictures were taken on a trail in a state park on Tennessee’s Cumberland Plateau. (Blake Farmer/WPLN)
Photo #3: Poison ivy can grow as a creeping vine on the ground. (Blake Farmer/WPLN)
Photo #4: Poison ivy can take over a dead tree, like this one on the Virginia Tech golf course. From afar, it looks like it could be an evergreen. Up close, it becomes clear that this is a nightmare of nature. (Courtesy of John Jelesko)