Beware the poison ivy

I try to keep the area around my house as diverse as possible with a wide range of settings, natural and managed, that promote an extensive variety of plants (mostly weeds) and insects. But this wide diversity of biological organisms is causing some angst in the household.

Of the many plants species growing in the “wild” area of the yard is poison ivy. My oldest boy claims that he can get rashes by just looking at the plant or standing by a patch. This is one of many popular myths with this plant.

The active ingredient in poison ivy, an oil called uroshiol, does not vaporize so an individual must come into contact with a plant part such as leaves, roots or stem. However, the oil can travel in smoke if the plant is burned.

There have been reported instances where a pet dog can run through poison ivy and transfer the oil on its hair to human hands when petted.

Regardless of how it is being moved around, I repeatedly have showed my children, including the oldest, how to spot the different stages of poison ivy and in different seasons.

One of the difficulties with poison ivy identification is the look-alikes. In the “Weeds of the Northeast” by Richard Uva, he describes other plants that look similar to poison ivy. The biggest misidentification occurs with Virginia creeper. Both plants are vines that either can trail on the ground or climb nearby structures in very similar settings, such as fence rows. The two often grow side by side.

One key difference is how they attach to structures as they reach for the sky. Poison ivy sends out aerial rootlets that adhere to trees, fences, or rocks. The aerial roots give the stem a hairy appearance.

Virginia creeper climbs by sending out tendrils to twist around nearby structures with tiny little “suckers” at the end that adhere to anything that doesn’t move.

The big confusion between the two plants is the leaflets. Poison ivy has three leaflets whereas Virginia creeper has three to seven leaflets but most of the time it has five.

Leaves on both plants turn a nice red color as the autumn months approach.

I have pointed out all these differences to my son so he could avoid poison ivy, but somehow he keeps getting rashes.

Or, I could be completely snookered by my son. He may know exactly what poison ivy looks like and is intentionally coming into contact with the plant when he is chopping wood, weed-eating or brush clearing. This results in a rash and he then is prohibited from all activity such as chopping wood, weed-eating or brush clearing until it clears up on his skin and I make another futile attempt to clear up the poison ivy patch.

Butzler is a horticulture educator with Penn State Cooperative Extension-Clinton County.


Virginia-creeper Virginia-creeper with the typical 5 leaflet pattern

Poison-ivy Poison-ivy with the typical 3 leaflet pattern

OR you could go with this idea

Photo 1 caption could be: After reading the article, can you spot the Virginia-creeper in the picture? Go to page B-4 for the answer

On page B-4 (or whatever page you want to put the picture on ) would be Photo 2 where the Virginia-creeper leave is circled amongst the poison-ivy