Leaves of three: Let them be?
‘Tis the summer season, and we often spend considerable time sharing how to grow desirable plants, but we often don’t share information about undesirable plants. Poison ivy and poison oak are two such plant species.
So, the following is offered to dispel some myths about these challenging plants and their effect on humans:
Myth: Poison ivy rash is contagious. Fact: Rubbing the rashes won’t spread poison ivy to other parts of your body (or to another person). You spread the rash only if urushiol oil – the sticky, resinlike substance that causes the rash – has been left on your hands.
Myth: You can catch poison ivy simply by being near the plants. Fact: Direct contact is needed to release urusiol oil. Stay away from forest fires, direct burning, or anything else that can cause the oil to become airborne such as a lawnmower, trimmer, etc.
Myth: Leaves of three, let them be. Fact: Poison sumac has seven to 13 leaves on a branch, although poison ivy and oak have three leaves per cluster.
Myth: Do not worry about dead plants. Fact: Urushiol oil stays active on any surface, including dead plants, for up to 5 years.
Myth: Breaking the blisters releases urushiol oil that can spread. Fact: Not true. But your wounds can become infected and you may make the scarring worse. In very extreme cases, excessive fluid may need to be withdrawn by a doctor.
Myth: I’ve been in poison ivy many times and never broken out. I’m immune. Fact: Not necessarily true. Upwards of 90 percent of people are allergic to urushiol oil, it’s a matter of time and exposure.
The more times you are exposed to urushiol, the more likely it is that you will break out with an allergic rash.
For the first time sufferer, it generally takes longer for the rash to show up — generally, in 7 to 10 days.
Source: University of Connecticut IPM and Poison Ivy Information Center
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For control techniques, contact your local Extension office.
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Cathy Brady and Don Fretts are educators with the Penn State Cooperative Extension, an educational network that gives people access to the resources and expertise of Penn State University.
Penn State Cooperative Extension is funded by the U.S. Department of Agriculture and state and county governments. Local extension educators and volunteers can be reached at fayettext@psu.edu or by phone at 724-438-0111.
For more information, check the state’s extension website at www.extension.psu.edu.