"Itchy Stuff"

POISON IVY: Itching To Tell 
Tips on Controlling This Rash

This vine can be found sprawling on the ground or climbing into trees.As a Master Gardener, I believe that almost all plants, even weeds, have some redeeming qualities. The one exception, however, is poison ivy (Rhus radicans).

Touching the poison ivy plant causes a painful rash on skin (allergic contact dermatitis). It is caused by a toxic oil, urushiol (you-ROO-shee-all), found in the sap. All parts of the plant, even the roots, contain the oil. Urushiol will start to penetrate the skin within a few minutes after exposure. In sensitive people (85% of us), a rash usually appears within 12-48 hours. Redness, blisters and swelling may follow. It may take 10 days or longer to heal.

The rash may seem to spread, but actually, the new areas of blistering are usually because thicker skin (forearms, legs and trunk) absorb the oil slower. The rash is spread by the oil and not by the sores. Scratching the blisters will not spread the rash, but scratching may introduce bacteria from your fingernails and infect the sores. The rash is not contagious.

The rash can be acquired in one of three ways:

  1. Direct contact - by touching any part of the plant.  Rashes have even developed when the vines were mistakenly cut for Christmas wreathes.
  2. Indirect contact - by touching any object, garden tools, clothing or animal fur that was in contact with the urushiol oil. The chemical can remain active on objects for more than a year.
  3. Smoke, airborne particles. NEVER BURN POISON IVY. Smoke from burning ivy can cause skin or lung injury. Inhaling the smoke can be fatal. Urushiol can remain active in dead plants for several years. You can acquire a rash in winter by burning wood that has the oil on it.

If you are exposed to poison ivy, the American Academy of Dermatology recommends these steps:

Identifying Poison Ivy

"Leaves of Three...Beware of Me"The best way of dealing with poison ivy is to identify it and avoid it. This perennial woody species is native to our area. It thrives in sun or shade, as long as moisture is adequate. Poison ivy spreads by creeping rootstocks or by seeds in bird droppings.

Fruit of the poison ivy plant.Each compound leaf has three oval leaflets that are 2-4 inches long. The middle leaflet is on a longer stalk. The compound leaves alternate along the stem. The leaves can be either smooth or dull; the leaf margins are coarsely toothed or lobed. The plant grows as a creeping vine, climbing vine, or even as a short shrub. The vine can grow up to 2 inches thick and up to 75 feet long. In winter, the vine and its root-like attachments resemble a hairy rope.

In fall, the leaves are among the first to turn color - red or yellow. Green fruit matures to ¼-inch white berries by fall. Tiny vertical ribs on the fruit resemble a miniature peeled orange. After the leaves are gone, the fruit is the major way of identifying the plant.

 Getting Rid of Poison Ivy

In southern areas Poison Ivy grows to great lengths each year.You can get rid of the poison ivy by mechanical or chemical means.

Do not mow it -- toxic leaves will spread. Instead, small patches can be smothered with newspaper or plastic. Boiling water poured onto small patches can be effective; repeat applications may be needed.

The plant can also be pulled out. This may be your only option if favorite ornamentals are growing nearby. It is probably best to mark the patch with spray paint in summer, then wait until late fall or early winter when most of the vegetation is dry. Be sure the soil is moist -- pulling plants from dry soil can cause roots to break and resprout later.

Be very careful in pulling down the vines; every part of the plant is toxic. Wear gloves and protective clothing. Use a plastic bag as a shield between you and the poison ivy, and pull out as much of the plant and roots as possible. Invert the plastic bag over the plant and seal the remains for trash removal, or bury the plant so deeply that it will decompose undisturbed.

Poison ivy has attractive fall color.Carefully wash all clothing (including shoes) and tools in detergent/soap and water when you are done.  Rubbing alcohol is also a good cleaner. If you take the clothes to a dry cleaner, put them in a plastic bag and label it "contaminated by poison ivy."

Several chemical controls also are available. Look for one that is especially made to kill poison ivy or brush. The ingredient TRICLOPYR is very effective and recommended. Others include 2,4-D, MCPP, glycophosphate and dicambra. The article, "Poison Ivy Control" by Lantagne and Kells of Michigan State (see references), presents an excellent review of available brush killers. "Poison Ivy Identification and Control" by Kevin Schoessow, Area Agricultural Development Agent (Wisconsin), is also worthwhile.

 When using chemical controls:

  1. ALWAYS READ THE LABEL COMPLETELY AND FOLLOW DIRECTIONS. 
  2. Use protective equipment and clothing when spraying.  Wash everything that comes in contact with the poison ivy plant. Leaving tools out in the sun will not break down the urushiol.  
  3. Treat leaves when they are fully grown, but before they change color in fall. Do not the soil around the plants. 
  4. For maximum effectiveness, apply brush killer when air temperature is 60-85 degrees.
  5. Apply in the morning or on a calm day to prevent spray from drifting to desirable plants nearby. Careless application of brush killer can destroy very large ornamental trees. Shield other plants if necessary, before spraying. Hold the spray head close to the poison ivy leaves.
  6. Check the weather.  It is best to apply chemical during a stretch of dry weather, so the chemical does not wash into the soil. 
  7. Check often for regrowth and reapply the spray if necessary. Allow intervals of at least two weeks before respraying. For a full year, watch for regrowth.

References:

– Joe Baltrukonis, Master Gardener

Additional Information:

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