February 2011 Articles

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Deal Carefully with Poison Ivy

Deal carefully with poison ivy By Dan Gill, LSU AgCenter
Anyone cleaning out overgrown areas or even just pulling weeds should beware. Poison ivy may be growing among the plants you’re handling. By late summer, poison ivy has had months to grow in your landscape, and you may find you have areas where the vine is present. This may be particularly true in out-of-the-way areas behind garages and along overgrown fences. Recognizing poison ivy Poison ivy is a tall, climbing, deciduous vine that is leafless in winter, so now is a good time to look for it because it has leaves on the vines. As it climbs tree trunks, wooden fences or other flat structures, the stem produces many small roots that cling to the surface. This is a good identifiable characteristic of the vine in case you can’t easily see the leaves. Plants are very common along fences and at the base of trees, and seedlings are often found in garden beds. Poison ivy has a characteristic compound leaf consisting of three leaflets. A commonly used rhyme to remember this is, "Leaves of three, let it be." The leaves are 2 to 4 inches long and dull or glossy green with pointed tips. The margins of the leaflets are variable, appearing irregularly toothed, lobed or smooth. Young foliage is often shiny with a reddish tint. Preventing rashes The agent in poison ivy responsible for causing the dermatitis is urushiol. It is found in every part of the plant, including the leaves, stems, flowers and even pollen. If poison ivy is burned, the urushiol can be present in the smoke, and contact with or breathing the smoke could be dangerous for people who are allergic. A significant portion of people are allergic to urushiol, and sensitivity can change over time. Just because you were not allergic to poison ivy as a child does not mean you are not allergic as an adult. It is best to avoid poison ivy altogether. But if you do realize you have come into contact with it, prompt washing may reduce the reaction. Special cleansers are available at local drug stores. You might want to keep these on hand if you have had problems in the past. Lotions are also available that, when applied to the skin beforehand, protect the skin from the urushiol should contact occur. Controlling poison ivy In controlling poison ivy, one of the most important things to do is to periodically check your landscape carefully for seedlings or vines. Look for the three-leaflet leaves in out-of-the-way areas, under shrubs, along fences and by trees. Three methods can be effective in eradicating poison ivy in landscapes. The first is hand pulling or digging the vines out when the soil is moist; getting out as much of the roots as possible. Use long-gauntlet rubber gloves available at local hardware stores or dishwashing gloves when handling the vines. Put the plants into a plastic bag, seal it (in consideration for trash collectors) and throw it away. Be sure to wash your gloves with soap and water after handling poison ivy – or dispose of them. The second is to carefully spray the foliage with a systemic herbicide. This is only possible when the spray will not get on the foliage of desirable plants. If needed, nearby plants can be covered with plastic sheets or bags to protect them while you do the spraying. Be sure to wet the foliage of the poison ivy vine thoroughly. Systemic herbicides are absorbed by the foliage and enter the plant’s circulatory system, which sends the material into the vine’s roots, killing them as well. The herbicides glyphosate (Roundup, Eraser, Hi-Yield Killzall and other brands) or triclopyr (Brush-B-Gon, Brush Killer and other brands) are commonly recommended for poison ivy control. Herbicides that contain combination of dicamba (Banvel) and 2,4-D also work well. Once the vine dies, it may be removed. The dead leaves still contain the urushiol and should be handled cautiously with gloves. The third method is for larger, established vines growing up in trees or intertwined in the landscape. Spraying the vine foliage is not practical in these situations because of the potential to injure desirable trees and surrounding landscape plants. Poison ivy control in sensitive areas can best be achieved by the cut-vine method. Cut off the vine a few inches from the ground with loppers and immediately treat the freshly cut stump with undiluted triclopyr (Greenlight Cut Vine and Stump Killer). The vine that grew up in the tree or shrubs will die because it has no root system. The treated stump will die because the herbicide gets absorbed by the freshly cut surface and translocates to the roots. Applying the herbicide to the fresh cut is necessary because it prevents the stump from resprouting. This method is very effective and may be used any time of the year. Getting poison ivy off your property will probably take repeated herbicide applications. Older vines in neighboring yards may continue to drop seeds in your landscape. Watch out for this unwelcome plant and be prompt and aggressive in your efforts to control it.