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Health & Fitness

Invasive Plant Talk: Poison Ivy

Poison ivy was, of course, named for its ability to cause an itchy rash in most people. From the time we are children, we are taught to watch out for “leaves of three,” yet we still fall victim to poison ivy occasionally.

Poison ivy is a master of disguise. As a vine, it is able to climb along the trunk of a tree; a mature vine can have a diameter of several inches. When leaves are gone, a hairy, ropy stem remains, which is just as risky to touch, often blending with the bark of the tree. Poison ivy can also stay on the ground, appearing shrubby or like brush. It will often hide among other plants, such as ivy or pachysandra.

When we talk about invasive plants, we are usually referring to non-native plants. This isn’t true for poison ivy, which is native to the eastern US. In fact, the name “poison ivy” was reputedly given by Capt. John Smith, of Pocahontas fame. Poison ivy is an opportunistic plant that readily locates itself in disturbed soil, or after a fire. As farmers and homesteaders cleared land, poison ivy adapted enthusiastically to the new opportunities.

 There are actually two species of poison ivy common to our area: climbing (toxicodendron radicans) and non-climbing (toxicodendron rydbergii). The two species have cross-bred so frequently, that poison ivy can have a range of characteristics and habitat. Poison oak and poison sumac, rare in our area, are part of the same genera, despite the different common names. It seems that these plants are only irritate humans. Goats will enthusiastically eat poison ivy, house pets are unaffected, and the red fall berries are a favorite food for birds.

 How do we get poison ivy? As you probably know, the leaves, stems and vine exude an oil called urushiol, which causes contact dermatitis. Some people are more susceptible than others, and some conditions like sweating which opens our pores, can make us more vulnerable. The urushiol oil can be transferred to clothing, other plants, or the family dog, and then be transferred to us. Poison ivy is not contagious, and it does not spread. The urushiol however, can remain potent indefinitely. So the work gloves or tools you used last year may still be able to cause a rash today.

 According to doctors, rinsing with lots of cool water, then gently lathering with soap, is the best way to remove the oil from your skin; warm water and scrubbing will only open up pores, making your skin more vulnerable. There are over-the-counter medications available for mild cases; you should seek medical advice if the rash is serious.

As for horticultural advice: how do you get rid of poison ivy? Carefully. Remove the entire plant, when possible, trying to keep the roots intact: roots spread underground and can be extensive. When this isn’t practical, there are sprays (such as Roundup) that can be applied to the leaves or you can cut the plants and apply a brush killer (such as Brush-B-Gone) to the stems. Remember, these sprays will kill every green thing they touch - not just the poison ivy! I suggest using hand tools on poison ivy, rather than a string trimmer that could cause the oil to spray. Similarly, mowing it can shred the leaves and cause them to disperse. It would be over-optimistic to think the poison ivy will disappear in a single season. However, if you persevere, it can be eradicated.

 I’d like to put in a plug here to hire a licensed professional (such as Almstead ) for controlling an invasive plant like poison ivy. A plant health care specialist has access to different, and often more effective, products than a consumer does. They will also have the equipment and experience to safely mix and apply these controls. Finally, they have the facilities to dispose of unused products and clean their equipment in an environmentally-responsible manner.

Careful cleanup is always important after coming in contact with poison ivy. Wipe your tools with alcohol (then oil them after they are dry). Hose off your boots, soap them, and hose them again. Make sure you wash all your clothes and gloves - and yourself.

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