Written By Sheila Herbst
Last winter my husband and I took out an old fence behind our house. We suspected that hidden among the honeysuckle, something more sinister was lurking: poison ivy. We were right. Spring brought a neat line of poison ivy plants where the fence had been. Summer saw the poison ivy spreading rapidly, encroaching on our backyard on one side, attempting to take over our six-acre field on the other.
First I mowed the area, adjusting the mower blades to the lowest possible setting, but before the week was over, even more plants were back. So I got out the weed-eater and had at it. Two hours later I was covered with tiny pieces of wet leaves. I did a little more yard work and then called it a day, taking a hot shower to be on the safe side. The next morning I woke up to an unbearable itching on my legs, arms and neck.
I had encountered a monster: one that has wide-reaching public health implications, and indeed, may have an indirect, though significant, interaction with global warming.
Poison ivy ranks high among the most medically problematic plants in the United States. According to the American Academy of Dermatology, 10 to 50 million Americans each year develop an allergic rash after contact with the poisonous plants.
Dr. Linda Stein Gold, a dermatologist in West Bloomfield, Michigan, sees about 10 cases of poison ivy a week in the summer.
“About 85 per cent of all people are allergic to these plants,” she said. “Only 15 per cent are resistant.”
It is the oil, urushiol (pronounced you-ROO-shee-ol), that causes the allergic reaction, either by direct contact with the plant or by indirect contact: touching an object upon which the oil is present; for example. a shovel or rake.
The rash develops 12 to 48 hours after contact. It starts as an itchy spot or patch. In this stage the rash can spread and cover a large area of the body. All parts of the body are vulnerable, but the eye area is especially so. Often, raised, fluid-filled blisters will develop.
For treatment Dr. Stein Gold said, “Topical steroids are helpful. For extensive involvement oral steroids are sometimes necessary.” For my rash both were prescribed.
Unfortunately for those of us who live in areas where poison ivy grows, that is, all of the United States except Alaska, Hawaii and some desert areas, poison ivy is becoming more abundant and more potent. Experts believe that rising carbon dioxide levels caused by global warming are to blame.
According to a 2004 Cornell study, part of the Cornell Cooperative Extension Agriculture and Food Systems Program, “There is increasing evidence that rising CO2 and/or temperature could impact the degree of contact dermatitis inflicted by poison ivy.”
The study indicates that the influence of increasing amounts of poison ivy needs to be examined in greater detail: “Weeds impact public health directly through allergies, contact dermatitis, physical injury and toxicology. Indirect effects may include botanically derived pharmaceuticals, pesticide use, changes in nutritional value and changes in the food supply.”
A 2006 study by Duke University, the Free-Air CO2 Enrichment Experiment, supported these findings, “The CO2 growth stimulation of poison ivy exceeds that of most other woody species. Furthermore, high-CO2 plants produce a more allergenic form of urushiol. Our results indicate that Toxicodendron taxa will become more abundant and more “toxic” in the future, potentially affecting global forest dynamics and human health.”
Brian Campbell, a naturalist at Carroll County’s Bear Branch Nature Center, located at Camp Hashawha, is always very careful to avoid contact with poison ivy. The staff at Bear Branch only removes poison ivy if it encroaches upon a hiking path or outdoor educational area.
“It’s a native plant,” Campbell said. “It belongs here.”
But Campbell also got a bad case of the rash recently.
“We were pulling out the roots of a non-native plant,” Campbell said, “and there must have been a poison ivy vine underground that I didn’t see.”
Although Campbell is not certain that increasing carbon dioxide is contributing to an abundance of poison ivy and its greater potency, he did say that he and the Bear Branch staff have encountered a lot of it this year.
For his rash, Campbell used a natural remedy: jewelweed. The crushed fresh leaves help dry the weeping blisters and ease the itchiness. Jewelweed is one of the main ingredients in many over-the-counter poison ivy creams, such as Technu.
Campbell’s poison ivy advice: “Leaves of three, let it be.”
Although not all three-leafed plants are poisonous, Campbell believes that identifying poison ivy in any other way can be very difficult. Poison ivy leaves can be smooth or jagged and colored many different shades, from bright green in the spring to reddish purple in the fall.
It can have berries. It can appear to be a hairy vine climbing a tree, or, grow shoots that look like branches of the tree itself. It can also take the form of a low-to-the-ground plant, when the vine pushes up from underground. The only constant shape that poison ivy has is three leaves.
Campbell has heard of people eating small amounts of poison ivy to build up immunity but doesn’t recommend it.
“It’s just too risky,” he said, “An allergic reaction could cause someone’s mouth and throat to swell quickly.”
Similarly, Campbell notes that inhaling smoke from campfires built with wood contaminated by poison ivy can spread the oil to one’s breathing passages.
how not to get it
After my battle with the bumps, I learned that the best defense against poison ivy is avoidance. When hiking through the woods, wear a shirt with long sleeves, pants, socks and shoes or boots instead of flip-flops. When working in the yard, wear all of the above and gloves. If you do come in contact with poison ivy, wash all exposed areas with cold water, like a garden hose, within an hour. Take care not to touch any tools or clothing that came in contact with the oil. A cool shower with plenty of soap later is also a good idea.
If you still get the rash, there are many over-the-counter medications available to ease the itching. I keep a can of Band-Aid brand Calamine spray on hand at all times.
common myths about it
Poison ivy is only a danger in the warm months. Not so. Poison ivy is very much alive and able to cause an allergic reaction all year, in every season.
A weed-eater is a good way to get rid of poison ivy. Forget it. Using a weed-eater on poison ivy can spray the oil and, if you are barelegged, like I was, can cause a bad rash. And if you have open scratches and the oil gets into your bloodstream,you could become seriously ill.
Burning poison ivy is an effective method of removal. No way. Poison ivy should never be burned, even in the winter when the plant appears dead. Poison ivy in the lungs can result in a trip to the emergency room.
Some people are immune to poison ivy. Not really. Although some people seem unaffected by poison ivy their resistance may change with age. Do not assume that because you never had the rash as a kid, you are immune forever.
A hot shower will “kill” the poison ivy oil. Uh-uh. As in my case, hot water can actually open your pores and spread the rash more quickly. If you do contact poison ivy, wash with cold water.
Scratching poison ivy blisters will cause the rash to spread and become contagious to others. No. By the time you have developed blisters, the oil is completely absorbed into your body and cannot be spread. However, popping the blisters should be avoided because it can lead to infection.
Raising goats is a full-proof way to rid any property of poison ivy. Nonsense. As a goat owner, I can testify that although goats are able to eat poison ivy with no ill effects, they will only eat it if nothing else looks tastier, like the flowers in your garden. Also, like any pet, they require an owner who is knowledgeable and committed to maintaining their well being. Furthermore, they may not fit into your lifestyle or neighborhood.
removing it
Technically, there are two types of poison ivy, the climbing and non-climbing varieties, but they interbreed, look very similar, grow in the same places, result in the same rash and are equally hard to remove. There is no easy way to get rid of it.
Cutting, through mowing or weed-eating, causes spraying of the oil, and the plant is likely to grow back anyway, often even worse, until every last bit of roots have died.
Uprooting poison ivy, something I attempted to do but got scared when I saw the thick hairy vine and quickly buried it, can be extremely hazardous because you can release a lot of urushiol oil in the process. Broadleaf herbicides, which we are currently considering for our predicament, can be effective but must be handled with care. They can harm both people and the environment
can there be anything good about it?
Although you may find it hard to believe, poison ivy does have its good points. It feeds wild birds, deer, and other forest animals. It also holds the earth very well against erosion near waterways. Some experts believe that there may even be untapped medical uses for the plant. All the same, I wish it would pack its bags and head out of my yard.
