More than once, while leading a group at Audubon, I have been involved in an exchange that goes something like this:
Kid: “I’ve had poison ivy before.”
Mom: “No, honey, I think you had poison oak.”
Me: “Did you get it around here?”
Kid: “Yeah. In my back woods.”
Me: “Then it was poison ivy, not poison oak. We don’t have poison oak around here.”
The kid usually gets a big kick out of seeing his parent corrected in front of a group. On the other hand, technically, they are both right.
“Poison Oak” is the common name given to the genus Toxicodendron which includes seven species including Poison Ivy, Poison Oak, and Poison Sumac. (If you include the numerous sub-species, you will have more than seven!) Here in western New York, we have two of those species, according to the USDA Plant Database: Eastern Poison Ivy (T. radicans) and Poison Sumac (T. vernix). Western Poison Ivy (T. rydbergii) is found in counties surrounding Chautauqua, so it wouldn’t surprise me if we have that, too.
If you don’t spend a lot of time in the woods, you may not know how to recognize Poison Ivy. We have a poem: “Leaves of three, let it be. Vines with hair, beware!” But there are many plants with three leaflets and fuzzy stems. On top of it, Poison Ivy changes in appearance through the season. Don’t count on the leaves being shiny, for example! The picture above with my foot in it was taken in August when the leaves had lost their shine. This one was also taken in August, but it has some new growth on it. The large green leaf is probably only shiny because of rainwater. But the new little leaf is intrinsically shiny and red!
Notice that the center leaflet is symetrical, while the two side leaflets are heavier on one side with a notch. I think the side leaflets look somewhat like a mitten with the notch being the thumb. Of course, not all Poison Ivy leaves will look exactly like that, and there are other plants with 3 leaflets that can look very similar… But after a while, you can just tell the difference.
In some places, Poison Ivy makes a lovely ground cover. Sometimes in an effort to get its leaves to the sun, it may climb trees, often completely concealing the trunk of the host.
As far as I know, we have just one specimen of Poison Sumac at Audubon. Do you recognize this spot along the trail that goes around Spatterdock Pond?
It’s just after you have crossed the long boardwalk… right where the blowdown is… Just as you are about to enter the dark hemlock forest – there on the right side of the path – still bright green in the sun… That’s a Poison Sumac (Toxicodendron vernix)! (Click on the photo to go to Flickr where I’ve added a note to point it out.) The leaves look like this:
All of the plants in this genus contain an oil called urushiol. That is the culprit that can make you itch and give you a nasty rash. Apparently, it doesn’t affect animals or 10-15% of the human population. I might be one of those 10-15% since I’ve never had the rash… But I won’t be tempting fate by rolling it it, either.
At Audubon, it is pretty hard to find a poison ivy free area for certain games. Last summer at Day Camp, after enjoying a fine game of Camouflage, we suddenly realized that we had been playing in Poison Ivy. To prevent getting the rash, we washed with soap and water and rinsed and rinsed and rinsed. We used dishsoap, rather than a moisturizing hand soap. Dishsoap is designed to cut through oils and wash them away. The hand soap might have made things worse by moving the urushiol around on our skin.
None of us got the rash, thank goodness. I’ve since read that cutting the urushiol with isopropyl alcohol first, then rinsing with lots of water is very effective, too, at preventing the rash when you suspect exposure.
If you can’t get to either alcohol or water for quite sometime, look for a plant that often grows where Poison Ivy grows… Jewelweed.
Break off a stem of the Jewelweed and use the juices to wash your skin where you suspect Poison Ivy exposure. Follow up with other treatments as soon as you can.