Beware of Fall Attractions That Could Leave You Scratching!

 

“Leaves of three, let them be” is an old adage that’s been stopping us in our tracks for generations. It alerts us, of course, to the highly irritating plant, poison ivy. But what happens when the leaves are gone? Same toxic reaction as when the foliage is lush. Contact dermatitis, as it’s known in medical circles. A nasty, itchy rash to the rest of us.

 

At this time of year, the leaves on poison ivy are turning from yellow to bright red and various shades in between. It’s one of the first plants to drop leaves in the fall, perhaps enhancing your chances of being exposed because there are no “leaves of three” to count.

 

Where’s what to look for, particularly if you enjoy gathering plant materials for fall craft projects? Most poison ivy plants produce fruit, which is easier to see when the leaves are gone. The waxy-looking berries are grayish white in color, about a quarter of an inch in diameter and grow in clusters. Be aware, however, that some plants produce only male flowers, which don’t produce any fruit. Use caution, too, if you see any hairy-looking vines. Those are mature poison ivy plants that have been growing up trees and along stone walls. They send out rootlets that help them cling to vertical surfaces.

 

The thing about poison ivy that’s so irritating is the sap, called urushiol (yoo-ROO-shee-ol). It’s a nonvolatile oil that causes a severe skin reaction in the vast majority of humans who come in contact with it. The oil is in the leaves, stems, vines and roots. Brushing lightly against any of those parts is enough to transfer the sticky resin to your shoes, clothing, skin or family pet.

 

Although your skin must come in contact with urushiol to break out in a rash, it’s easily transferred from one object to another, and nonvolatile means it stays potent for a long time. You could pick up a toxic dose from your dog’s fur by petting him hours after he’s been exposed, then rubbing your aching neck. Rest assured Rover won’t be affected but it’s likely to leave you scratching. In fact, the oil you unknowingly picked up on your garden gloves this year will still cause an itchy mess next spring, if you get it on your skin.

 

So, how do you get rid of the noxious plant? At this time of year your options are limited to pulling or “grubbing” it out. The chemical means that are most effective must be applied in the active growing season, when foliage is lush. The problem with digging is that any piece of root or rhizome that’s left behind will become a full-fledged poison ivy plant come spring so make sure you’re thorough.

 

At no time consider burning out your poison ivy problem. “Nonvolatile” means urushiol won’t incinerate, either. It will, literally, go up in smoke. The oil attaches itself to soot particles and floats out of the fire. You could be exposed if the smoke blows your way, on your face or maybe in your lungs. This warning stands, too, for poison ivy vines you may have pitched onto your brush pile last spring or last year. Urushiol seems to have a half-life greater than plutonium. The stuff is slow to break down, whether the plant is dormant or dead.

 

What should you do if you find you grabbed poison ivy rather than the grape vine you thought you were reaching for? If there’s a stream nearby, wash your hands or exposed area in the cool water. It may not remove all the oil but enough to dramatically lessen the effect. Urushiol takes from only a few minutes to a couple of days to penetrate your skin and cause a reaction. How long it takes depends on your sensitivity, the thickness of the skin that was exposed, and how much you got. The palms of your hands are unlikely to break out because the skin is so thick but you could still transfer the oil to other parts of your body. Cool temperatures also help close up the pores on your skin, which may give you the extra time you need to get a more thorough scrubbing.

 

Too bad poison ivy has that one really nasty characteristic—urushiol—because otherwise it’s an ideal landscape specimen. It’s easy to propagate and spreads quickly making it highly effective for erosion control. The color is appealing: bright green with a reddish tinge in early spring and brilliant crimson in the fall. Poison ivy is a great source of food for wildlife, which isn’t affected by the noxious oil. Bears, rabbits and deer eat the bruit, foliage and woody stems. A variety of birds feast on the berries. It will grow just about anywhere: along roadsides, at the beach, on the edge of woods, and across fields, even in your formerly poison ivy-free vegetable garden. (You can thank the birds for that.)

 

For the record, there are additional characteristics that distinguish poison ivy from other three-leaf plants, but there are plenty of exceptions. Some varieties grow with five- or seven-leaf clusters. The leaves may be shiny or dull, toothed or lobed, and hairy or smooth. The plant may be found as a dense groundcover, a long vine or a small shrub. In other words, it’s easy to mistake poison ivy for some other harmless plant.

 

Next spring, when you’re ready to take on the world and eradicate your property of all noxious pests, call the Family, Home & Garden Center for more information. The center is staffed 9:00 a.m. to 2:00 p.m. Monday through Friday. The toll free number: 1-877-EXT-GROW(1-877-398-4769). Trained volunteers will explain what to look for and how to control it. Chances are you’ll talk with someone who has first hand experience.

 

By Jackie Bower, Master Gardener, University of New Hampshire Cooperative Extension