Poison Ivy in the Laundry

Posted by on Oct 29, 2020 in Unmowed Blog | 0 comments

shiny poison ivy leafNow here’s the amazing thing about poison ivy. It’s really quite helpful when you do the laundry.

Urushiol, the chemical that causes the horrible allergic reaction, is water-resistant. It’s hard to wash off your skin. It’s hard to wash off your clothes. Okay, it’s hard to imagine that this could ever be a good thing.

The interesting thing about urushiol is that it oxides when exposed to air–it turns black. A deep, dark, waterproof black. Urushiol was the original permanent marker. Before the invention of magic markers, it was hard to label clothes with a mark that wouldn’t wear off in the laundry. Most inks would wear off in time, especially considering the churning in boiling water and pounding with a pole, and scrubbing on a washboard that laundry used to entail. So how to label the clothes? Embroidering one’s initials on the cloth was about the only permanent solution.

Except for urushiol, that is. The black sap is practically impervious to removal. Urushiol has been used around the world as a laundry aid. Poison ivy and poison sumac were used in this country for laundry-marking, incredible as it sounds. They were sometimes referred to as “marker weed” and “mark tree.” True story.


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