Tuesday, February 15, 2011

Are you itching to get out into your garden? Watch out for poison ivy!

Since I’ve been itching to get out into my garden this winter, I decided to spend some time a few weekends ago pulling out vines and digging up plants along the edges of my property that were little more than dead-looking, leafless stalks and vines.

My body was completely covered, with long pants, socks, shoes, a long sleeved jacket and gloves. And still, I developed a rash that is most definitely poison ivy. Since I have had some pretty bad outbreaks of poison ivy induced rashes at various times of my life, I feel fortunate that this time I only have a small, ½” rash that developed in an area that must have gotten exposed in between my long sleeves and my gloves. But as anyone who has ever gotten into poison ivy knows, that little rash itches enough to cause all kinds of misery.

So the lesson learned is, you CAN get poison ivy in the winter.

Poison ivy is fairly easy to identify when it is displaying its beautiful “leaves of three”. The Virginia Cooperative Extension provides this description:

Poison ivy can grow as a groundcover or small bush in woods, fields, at the edges of openings and trails, and pretty much everywhere else. Poison ivy also grows as a vine that climbs on trees, barns, and fences for support. The vine has small aerial roots along the stem that make it look like a fuzzy rope and often has much longer aerial roots as well. Because the plant grows in so many different forms, its leaflets are the best way to identify poison ivy. The leaflets grow in clusters of three. Hence the old saying "leaves of three, let it be." These leaflets are from two to four inches long with pointed tips. The middle leaflet is usually larger than the others. The edges of the leaflets don't always look the same. They might be smooth, or they could have teeth. The leaflet surface can be many different shades of green and appear glossy, dull, or in between.

But since poison ivy is a deciduous plant, it loses its leaves in the winter, making it very difficult to identify. As the leaves turn yellow, orange and red in the autumn, they begin to drop and may no longer be “leaves of three”. And of course, in the winter, they fall off completely, resulting in nothing but bare sticks and vines.

Unfortunately, these dormant, leafless poison ivy plants still contain the irritating oil, urushiol, which can cause the insufferable rash. In fact even dead poison ivy plants may cause an allergic reaction for several years.

What Causes the Rash?

All parts of the poison ivy plant, including the roots, stems, bark, and leaflets, are poisonous year round. The blistering rash people get is caused by an oily toxin known as urushiol. The most common way this toxin gets on your skin is when you touch the plant, especially one that has been damaged in some way, such as being stepped on or run over with the lawnmower. The toxin is oily and sticky, and is easily spread around when you touch other parts of your body. For example, if you are weeding a flower bed and pull up some poison ivy, then wipe your face later on, the chances are pretty good that a rash will develop on your face. You also can contract the rash by picking up the toxins from animals, clothes, or other items that have been in contact with poison ivy. And, if poison ivy is burned in a brush pile, the resulting smoke carries the toxins. It is very important that you avoid breathing the smoke of burning wood or brush if poison ivy might be part of the pile.

Poison ivy grows fairly quickly and spreads by underground rhizomes. Other plants are started by birds and small animals which love the berries and quickly spread the seeds.

Poison ivy can be tackled (I have yet to see any real evidence in our heavily wooded yard that it can be completely eliminated) by either hand pulling and digging or by spraying the foliage with non-selective herbicide. Since there is no foliage on the plants in the winter, herbicides are not a winter option. However, if you have already identified poison ivy in your landscape during the warmer months, winter can be a good time to remove some of the plants by digging and hand-pulling because the plants are more dangerous in the spring and summer when the oil content is the highest.

Before removing any plants that could possibly be poison ivy, consider these Facts and Tips:

1) Dormant or dead poison ivy is very difficult to identify. You can sometimes identify the larger vines by the hair-like roots growing from the vines.

2) You can develop a severe allergic reaction to poison ivy even if the plants are dormant or dead.

3) The oil from poison ivy plants can make its way through thin layers of clothing, especially if you are sweating while you work.

4) Wash your hands with soap and cool water immediately after touching anything that is suspected of being poison ivy. Warm water may cause the resin to penetrate the skin faster.

5) If burned, the oils in the smoke can cause severe allergic reactions.

6) The oil from poison ivy can be picked up on tools, clothing and the fur of pets and later transferred to your skin. Anything that may be carrying the oil should be thoroughly washed.

7) Always wear long sleeves, long pants, shoes, socks and gloves when handling poison ivy. Launder the clothing separately from the family laundry and wash your hands after placing the clothes in the washer.

8) Heavy growths of poison ivy should never be removed by hand because of the obvious hazard. When leaves are present, spray them with a non-selective herbicide or poison ivy killer. Use these with care to protect other plants from being harmed by the spray.

9) Control with chemicals is most effective during active growth especially in early to mid summer. The chemicals are most efficiently absorbed and translocated through the leaves of the plant at these times.

10) However, winter is a good time to sever poison ivy vines at ground level and paint the severed edge with a suitable herbicide.

11) Be careful not to bring firewood into the house with poison ivy vines attached.

12) Contact your local Extension agent for more information on preparing herbicide mixtures and applying them safely; and always be sure to follow the directions on the product label.


Poison Ivy: Leaves of Three, Let it Be! – Virginia Cooperative Extension

Poison Ivy(pdf file) – Maryland Cooperative Extension

Poison Ivy, Oak and Sumac Information Center

Outsmarting Poison Ivy

Photos courtesy of http://www.poison-ivy.org/

Toxicodendron radicans– Wikipedia entry with good photos

Winter Weeds: Poison Ivy - a blog post with photos of poison ivy in the winter

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