Despite the suffering it causes each year for so many people, the power of poison ivy is underestimated.
It is particularly dangerous this time of year because most people don't recognize it. The signature three leaves may not have appeared yet, but its toxic oil is always there, ready to make you itch.
I've been wandering Penn's Woods for nearly six decades, and painful experience has taught me how to identify poison ivy in all four seasons. There is not much in this world I hate, but yes, I do hate poison ivy.
Even if its three leaves aren't visible, the noticeable white berries hang on the plant through summer, fall and winter, providing food for birds who seem to be immune to the toxin.
In early spring, however, there is only one telltale sign to look for: a furry, hairy vine.
About this time last year, a co-worker asked me how she'd gotten poison ivy (and quite badly, too) while clearing her garden. I asked her to return to her garden, take some photos and bring them in for me to see.
When I saw a hairy vine snaking along the fence post, I knew.
Now a lot of gardeners and outdoorsmen will say: "Who cares? I'm immune. I don't get poison ivy."
Well, yes, you do. Maybe you haven't got the itch yet, but you will. Its toxin is such that the more you come in contact with it, the more likely you are to be affected. You don't build up an immunity.
So this message is for everyone -- gardeners, outdoors lovers, even folks who just go for a walk in the woods occasionally: Let's be careful out there!
For your sake, I've updated that old saying about poison ivy, hoping it will help someone avoid that terrible itch:
"Leaflets three, you may not see ... but a furry vine, just let it be!"
Pete Zapadka is a PG online editor who takes photos of beautiful wildflowers -- and sometimes hairy vines. Contact: email@example.com or 412-263-1857. Twitter: @pzapadka.