The Weed in Winter

poison ivy in winter

When poison ivy climbs it grows thousands of tiny red root hairs to attach to the tree, wall, or other vertical surface.

No other vine has such distinct, tiny, red, hairy roots, so look out for this in winter. And remember, the vines (and roots) are still full of urushiol oil, so you can get a nasty rash even in winter. Cutting firewood is one way people run afoul of poison ivy in winter.

On the other hand, the ground vine is very hard to spot in winter as there is nothing special about it: no hairy roots, no leaves of three. Just a woody vine waiting to mess with you.