Poison Ivy

Urushiol may not be your friend!

In response to a question that came up in the group, Cris writes...


You may not have heard of urushiol, but once you hear the words “poison ivy” you might know right away what link urushiol has to that plant. Urushiol is the oil in poison ivy that causes the allergic, very uncomfortable reaction, in most people when they come in contact with the plant. But, did you know that oil capable of causing such pain and agony, is able to be that problem year ‘round? It’s not only the “leaves of three, let it be” adage to keep in mind when we think about the dreaded poison ivy in New England. Poison ivy vines and roots, without leaves, berries or flowers, causes the same reaction if you touch it. Poison ivy vines grow along our beautiful stone walls, climb our garden fences, and climb up trees. You can find poison ivy growing as a ground cover, too, along the side of driveways in condos and shopping malls even. Touching the vine or roots will get the urushiol oil on you, and you’ll find yourself with a rash breaking out up to a week later. What else does this mean for gardeners? If you try and remove poison ivy vines or plants with a shovel or hoe or other garden tool, that tool will have the oil on it, which remains viable for months to come. It’s important to clean tools that have come in contact with urushiol/poison ivy with soap and water or with rubbing alcohol. Our pets are not susceptible to the rashes it causes, but their fur can harbor the oil if they are gallivanting in an infested area. So, be mindful that it’s so much more than the leaves of three that can bother you! 


Check out poison-ivy.org for photos of the plant throughout the seasons. Also, the UNH Cooperative Extension (www.extension.unh.edu) site, “What can I do to get rid of the poison ivy in my yard?” article has valuable information about poison ivy. The vines, this time of year, are easy to identify, due to their numerous fuzzy aerial roots. We think of roots as being under the ground surface or in our house plant pots. But in the case of poison ivy, the vine sends out roots in the air, looking to grab on to anything available to continue growth. They are distinctive, with their fine fibers seen from a distance. Urushiol is abundant all over the plant, so don’t touch! 


Poison ivy could have been flourishing in a firewood pile, and be clinging to firewood you might bring in to your home. Carefully look at the wood before you lift it off the pile – any clinging vine material could be poison ivy, so check for the hairy, fine roots that are stretched on logs. 


With the right precautions, you won’t get the poison ivy rash and blisters in the winter, but people do! This is the time of year to notice where it’s growing, once you identify the roots and tendrils on the vine without the greenery to distract you. Once you see where it’s growing, you can make notes to remember where it is when you go back to that area to enjoy spring weather or summertime flowers, or autumn colors. Poison ivy will likely be some of the earliest colorful autumn plants out there, and may linger with its red and orange vibrancy long after other leaves have browned and fallen to the ground. Don’t be tempted to admire it too closely! 


Some folks are not affected by urushiol, but most are. Urushiol is found in poison sumac, poison oak and in parts of the mango plant and around the world, including in Chinese laquer trees. Some research has produced some great products available in pharmacies, outdoor supply stores and – Amazon. There are swabs you can touch a plant in question with, and the color change on the swab will let you know if urushiol is in that plant. If you are very susceptible to the rash, or if you want to be outdoors more and worry less, have a look at these types of products to help you avoid the problem before it happens. Don’t be scared – be informed! 

Close up of poison ivy tendrils in wintertime growing up a tree

Poison ivy tendrils on a tree in winter. Photos courtesy of poison-ivy.org