Even as temperatures cool, poison ivy can still cause allergic reactions. This time of year, identifying poison ivy can get even trickier, because their colors change to yellow or bright red, and it has green or white berries. There are even cases of children picking them, or people using them for ornamental wreaths, because they look so pretty. New research also suggests climate change could be causing poison ivy to have larger leaves, and might be making them more toxic.
About eight in 10 people are allergic to poison ivy. “It’s a plant that is so close to so many people, and we actually know remarkably little about the biology of this plant,” said John Jelesko, an associate professor at Virginia Tech and one of the authors of a new study that reveals the shape of poison ivy leaves can be incredibly varied, and therefore difficult to correctly identify.
If you went to summer camp you probably know, leaves of three, leave them be. But the shape of poison ivy leaves varies widely. Some are completely smooth around their edges, others have notches.
“If it’s hard to identify, it’s really hard to avoid,” Jelesko said. Poison ivy tends to grow along fence lines and roads. Jelesko said in some of his past studies along the Appalachian Trail, he’s found that hikers were more likely to encounter it when they left the forest and entered a field or crossed a road, than when they were hiking.
Jelesko said he hopes to continue research to discover if the DNA of poison ivy can tell us why the leaves look so different.
“And see are these different species, or is this thing just, for some reason, being a shape-shifter? And we just don’t understand any of that,” Jelesko said.
