All about Poison Ivy

By Rita Lynn

             Early this fall, when trees were just barely starting to show color, I was walking in the woods and spotted brilliantly colored leaves on vines growing up trunks of trees. These splashes of red, orange and gold stood out in the woods and pierced an otherwise gray day with beauty. As I suspected, closer inspection revealed that the show was being put on by poison ivy.

Everyone who spends any time outdoors should be able to identify this plant because of its ability to cause uncomfortable and sometimes dangerous rashes to susceptible people. Perhaps you have heard the saying, “Leaves of three, let it be!” The plant does indeed have clusters of three leaflets, with one leaflet at the end of the leaf stalk (petiole), and the other two leaflets arising opposite each other lower on the petiole. These lower leaflets are often shaped like mittens, but in truth, the color and shape of the leaves is highly variable. Poison ivy (Toxicodendron radicans) grows in many forms, from bushy plants to vines that climb entire trees, and it is found all across the United States. Oil, technically called “urushiol,” produced by all parts of the plant and most potent in the sap, is what causes reactions in human skin.

Not everyone is sensitive to this oil. Some people haven’t been bothered by it and some get just a slight, short-lived itchy rash. Beware, however, if you haven’t ever reacted to poison ivy. Sensitivity can develop at any time, so it’s best just to avoid exposure no matter what. You can get a rash from touching any part of the plant, by being sprayed by the oil as the leaves are cut, or even by touching an object or an animal that has come in contact with the plant. Your skin absorbs the oil quickly, some say within half an hour. Therefore, washing with detergent – or even plain running water if that’s all that’s available – as soon as possible is important.   Once the oil is on an object, however, it is very stable and can remain potent for as long as a year. Consequently, contaminated objects need to be carefully discarded or thoroughly cleaned.

Treatment for mild cases of poison ivy rash involves using topical medication available over-the-counter. Interesting home remedies to relieve itching from such irritations include using heat in the form of hot water or a hair dryer, applying the sap from jewelweed, or spraying with deodorant containing aluminum. In the most susceptible people, the initial rash can develop into inflamed, swollen lesions with open weeping sores that can last for two or three weeks and may require medical intervention. Even worse, people have been known to suffer from exposure to their lungs from breathing smoke when poison ivy is burned, sometimes resulting in a need for hospitalization.

If you discover poison ivy growing in your yard, eradicating it requires caution and may take some time. By no means should you burn the plants or try to pull them up your bare hands. The best time to start the elimination effort is May through July when the plants are flowering. Spraying with glyphosate (sold as Roundup and other herbicides) is the safest method, although other plants in the area might be damaged. Vines should be cut off about 6 inches above the ground and the stump treated with the glyphosate according to package directions. The plant spreads by its tough roots as well as by having its seeds dispersed by birds. Eradication may take several applications of herbicide and efforts over several seasons.

Scourge that it is to humans, animals and birds are not affected by urushiol. There is much to be said in defense of poison ivy on their behalf.  Small animals, birds and insects use poison ivy for shelter, and birds then feed on the insects hidden in the vines. Mammals such as deer browse on the foliage. Perhaps most importantly, poison ivy produces grape-like clusters of white berries. Robins, grosbeaks, chickadees, finches and juncos are some of the birds that are attracted to the berries, available in fall and winter when other food is scarce. And dare we mention its function as a hardy ground cover, or that it is truly beautiful in the fall? So when you see poison ivy in the wild or even in a remote area on your property, stay away from it, but try to remember that it is a treasure to the environment and to the rest of the animal kingdom.

SOURCES

“Poison Ivy,” http://poison-ivy.org/html/faq.htm

“Poison Ivy,” www.fcps.edu/islandcreekes/ecology/poison_ivy.htm

“Poison Ivy,” www.gpnc.org/poison.htm

“Poison Ivy Control,” mdc.mo.gov/node/4686

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