If you hike a lot, or go for walks in parks, you’ve probably memorized what poison ivy looks like—and if you haven’t, you should. Leaflets clustered in threes, let it be, and all that. But as summer turns to autumn, there’s an important change to note: poison ivy can change colors just like the leaves on trees.
Even when the leaves are yellow or red, they can still contain the irritant oil (urushiol) that causes poison ivy’s infamous rash. All the other hallmarks of the plant still apply: leaflets in alternating clusters of three, growing along the ground or up a tree on a hairy vine, and, in the eastern US, even growing in the shape of a bush.
No matter the color of the leaves, you can get a rash from poison ivy if the oil stays on your skin for a few hours. If you suspect you’ve encountered it, use soap and water to wash any skin that may have come into contact with the plant as soon as possible.
