If you’ve ever had poison ivy, you know what a nuisance it can be—that itchy, blistering rash is enough to make you never want to go outside again (let alone, into the woods). And if you haven’t had it before? Well then you’re a lucky duck!

Whether you’ve had poison ivy before and never want to get it again, or you’ve never had it before and want to avoid it: This advice is for all of you. One groundskeeper has some very wise words for you on how to steer clear of this very annoying rash.

What is poison ivy?

Poison ivy is a plant known for causing a red, itchy rash and inflammation on the skin. About 85 percent of people in the United States is allergic to poison ivy, according to the American Academy of Dermatology.

However, no one is born allergic to poison ivy. “Our bodies become sensitized to poison ivy after an initial exposure,” says Joshua Zeichner, MD, director of cosmetic and clinical research in dermatology at the Mount Sinai Hospital in New York City. “Upon future exposure, our immune system becomes activated, leading to significant inflammation.”

How you can get it

The leaves of the poison ivy plant contain a greasy substance that can get into contact with the skin and cause the reaction. This oil is called urushiol, which is pale-yellow in color and is also found on poison oak and poison sumac.

Urushiol can also get on you through objects it touches, like the lawn mower, or pets who come into contact with it, like your dog. It can also be hiding in flower beds or mulch. So if you get the rash but don’t remember hiking in the woods, know that you can get it just from the oils.

And once it gets on you, it’s super hard to get off. “If you get it on your shoelace, then you tie your shoe and you wipe your forehead, you could have poison ivy on your forehead,” says Linda Radimecky, an interpretive naturalist at Afton State Park in Minnesota.

Once you get into contact with poison ivy, it can take 12-72 hours to develop on your skin and can last one to three weeks in total. Contrary to popular belief, poison ivy isn’t contagious.

How to recognize poison ivy

The more rain, the more poison ivy, and this year with all the rain that’s come, there’s been an explosion of poison ivy, so more and more people are coming into contact with it.

Luckily, there’s a pretty simple way to remember what to look for and how to remember it too. Check out this video for more info on poison ivy and the groundskeeper’s advice on recognizing poison ivy no matter what form it takes.

Did you know how to recognize poison ivy before watching this video? Have you ever gotten poison ivy or poison oak before? How long did it last when you got it and how did you get rid of it?