Home Curiosity A Scientist Provides Timely Advice About Identifying Poison Ivy Before It Turns...

A Scientist Provides Timely Advice About Identifying Poison Ivy Before It Turns Your Summer Into Hell


If you’ve ever picked up an itchy poison ivy rash, then you know how uncomfortable and irritating it can be.

John Jelesko, an associate professor of plant pathology, physiology, and weed science at Virginia Tech, had a close encounter with poison ivy in 2012, an experience which made him take an interest in this rash-inducing plant.

Jelesko was doing some yard work when he accidentally picked up poison ivy rash. Because he didn’t think it was anything serious, he decided to leave it untreated. And in approximately two weeks, he learned how uncomfortable this plant could be.

Jelesko explains that he had trouble sleeping while resisting the urge to “claw my itching flesh off.” In the end, he asked for his family doctor’s help.

Poison Ivy Outdoors Flora Nature Leaf Growth

This experience caused Jelesko to spend years carefully researching into a plant that he calls a “familiar stranger.” He’s studied urushiol, the chemical which triggers the rash, and the biology of the plant.

In what follows, we’ll present Jelesko’s timely advice about identifying this rash-inducing plant as well as some science behind urushiol, and what you should do if you’ve come in contact with the plant.

He explains that the tricky thing about avoiding the “familiar stranger” is that it’s very adaptable and it can take various forms in various environments.  

However, in order for you to identify the plant, you need to be able to recognize the leaf shapes. The leaves of poison ivy can have smooth, lobed, or jagged edges.

Another tricky characteristic of poison ivy plants is that they can grow in different shapes and sizes. For instance, in cities, they tend to grow as climbing vines, while out in the woods, they tend to grow as ground-creeping vines.

And that’s not all – poison ivy can grow as a shrub and it can also take over a dead tree.

What do you need to do when you’ve come into contact with the plant?

If you know you have touched poison ivy, here’s what you can do to ease the problem:

1. If you think you brushed up against the “familiar stranger,” wash with water and soap within a few hours.

2. To make sure you touched the plant, try tearing the leaf in half with gloved hands, and then put the sap on a piece of white paper. If it is really the “familiar stranger,” the urushiol oil will become black within half an hour.

3. If you’ve never picked up poison ivy rash before, know that the rash could take 7 days to develop. Whereas if you’ve had contact with the plant before, the rash can begin appearing in a day or two.  

4. Dermatologists advise that you soothe the rash with corticosteroid or anti-itch cream when you start breaking out.

5. And if the rash gets very bad, visit the doctor.