This happened to me, in a less extreme way. Clearing fallen, leafless winter brush... oops. There actually is a failsafe way to identify mature poison ivy, even

This happened to me, in a less extreme way. Clearing fallen, leafless winter brush... oops. There actually is a failsafe way to identify mature poison ivy, even without the leaves-- on the large stems, there will be "hair"-like roots. So, the leaf-identification exercise at that website is great, when in doubt look to the large stem/trunk of the plant. And if you see 1 large climbing poison ivy trunk, steer clear of all ivy-like brush in the same area.