I think the most of what we have is the poison ivy and it is deciduous. However, every part of the ivy is extremely poisonous. I've gotten a terrible case of it when I was digging up plants in an old homestead and we had to dig through ground cover vines. We had no idea those vines were poison ivy!

You can get the rash even in mid winter from touching roots, or stems which are dormant. When you are digging things up, you often disturb roots and get it this way so that is probably how you got it. Once you get it on your hands or tools, then you can spread it to all parts of your body that you touch. On trees the stems are hairy and that's a good way to identify dormant stems.