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Avoid contact with smoke that might come from burning poison ivy such as a burning leaf pile, or a brush or forest fire. Even a lungful of the air-borne poison ivy oils can be serious. Likewise, don't get the oil in your eyes. If either of these events occurs, get to the emergency room.

HOW POISON IVY WORKS
All parts of poison ivy, except, mercifully, the pollen, contain an oil called “urushiol”. Urushiol is chemically stable, so it doesn’t break down or evaporate easily; it’s sticky, so that it readily adheres to anything it touches; and it’s not water soluble, so it’s hard to wash off.

Urushiol is always active, even if the plant is winter-dormant or dead. Old lab specimens and unwashed camping gear have caused rashes. Even fire doesn’t destroy urushiol. When poison ivy is burned, the urushiol bonds with the soot particles, and floats off in the smoke.

Further, urushiol starts to absorb through the skin in minutes. It bonds with inner-skin proteins to create new compounds, which the immune system of 80 to 90 % of humankind treats as an invading disease. The itching, redness, and blisters are our allergic reaction to the plant. The symptoms can appear in hours, days or even a week after contact. Like other auto-immune disorders, a serious poison ivy bout can damage joints and internal organs.

Because it's an allergic reaction, the effect is cumulative. You might have no reaction at first but your immune system is only warming up. Additionally, the initial reaction will be less if your immune system is suppressed for any reason. Conversely, the allergic reaction increases as skin thins with age, and as your natural protective oils are thinned by washing, diet, age, or other cause.

Urushiol is not on the plant’s surface until secreted through even the smallest bruise. So you can brush the plant 50 times with no effect but, then, if the next piece you touch was crushed by a rake or chewed by a rabbit.…

Lastly, sticky urushiol not only adheres to anything it touches, it stays on the surface a long time, and it transfers readily from surface to surface. For example, it will transfer from the dog’s coat to your face. It doesn’t take much; urushiol is so potent that they say that a ¼ ounce could give the entire human race a rash.

PICTURES: Poison ivy around town, early summer 2005. Note that in both pictures some leaves have smooth edges and some are in the lobed "oak-leaf" form. Note also the sheen to the young leaves on the right.

LEAFLETS THREE, LET IT BE
It is best to learn recognize poison ivy and avoid it. Recognizing poison ivy, though, is tougher than it sounds because the plant takes many forms. In Stamford, it can be a climbing vine, free-standing shrub or ground-cover. The leaflets can be smooth-edged, lobed or partially lobed. There's nothing but gray stems and hairy rootlets in winter. The early spring color is bright, shiny red, followed by shiny or matte green leaves. The small flowers and berries are creamy white. The fall colors are purple, red, orange and yellow. The dead leaves on the ground can be very pale yellow or any shade of brown.

Look for the three leaves and an almost-always present sheen to the leaves. Learn to tell the various leaf forms and colors; if you’re not sure, treat the plant as poison ivy.

FIRST AID
Get the oil off fast. It’s not water soluble so using plain water or water plus an oil-based soap spreads the urushiol. Use an alkali soap like naphtha soap or a dishwashing soap with a "degreaser". Alcohol and other solvents for oil-based products also work. Take a shower-- not a bath -- or you could end up with a whole-body rash.

In the wild, use any available water. To get the oil off, use mud, baking soda, wood ashes or, if you can find it, Bouncing Bet (Saponaria officinales) (a useful European import, high in saponin, makes an oil-free soap). The juice of jewelweed (Impatiens capensis, I. pallida) is suspected to have urushiol-blocking compounds and is known to be anti-inflammatory; a tea or poultice made from plantain leaf (Plantago lanceolata, P. major) is also said to help for similar reasons.

There are over-the-counter products said to block the oil from entering the skin and/or remove the oil after contact. Some of these products are said to be more effective than others, so do your research.

PICTURE: Poison ivy about to burst in to flower on the big red oak in Hoyt Street Alley. May 2004

BACKGROUND AND HISTORY
Poison ivy (Toxicodendron radicans), a woody-stemmed perennial, belongs to the same family as cashew, mango, pistachio, and sumac. Poison ivy and poison oak are either a single species or about 15 – toxicologists don’t agree. In any case, poison ivy is native to North and Central America, and to parts of Asia. Early European visitors took the stuff home for the autumn garden; so it now also grows in Europe and Australia.

Only humans are allergic to poison ivy. Deer and rabbits relish the leaves. Squirrels nest in it. Bees make honey from it. Goats readily eat poison ivy, and, curiously, the toxins aren't passed into the goat milk.

Birds like the white poison ivy berries. As a result, the non-digestible seeds end up, fertilized with bird droppings, under roosting places. This works for the birds and the poison ivy. In the forest shade, poison ivy seedlings don't crowd out other plants, which works for the eco-system. However, as humans have cut back by forest, the poison ivy population has gotten out of balance. Today, you'll find poison ivy sneaking out from under of hedges all over town, climbing up trees along the highways, and forming free-standing shrubs along the Long Island Sound.

PICTURE: The winter look of poison ivy (on the big red oak in Hoyt Street Alley)-- note the red thread-like root hairs on the older vines and "polka dot" lenticels (pores) on the younger ones. March 2004

GETTING RID OF POISON IVY
Some conservationists, who would eradicate alien invasives such as porcelain vine, and Asiatic bittersweet, urge us to leave the native poison ivy alone. Poison ivy may be native but it is also an "enhanced species". This means that the species has gained an advantage from human contact. Examples of enhanced species include white-tailed deer, ragweed, cockroaches, and house cats.

When I was a kid, humans balanced out their poison-ivy-enhancing behavior by pulling the plant up anywhere it was found. Today, I think we should do the same.

It is best to root out the whole plant while it is small. Do as the "pooper-scoopers" do: use a couple of layers of plastic shopping bag as an oversized glove to protect your hand while pulling up the plant; then, reverse the bag to cover the plant; tie and drop in the garbage.

Larger plants and vines can be cut off at ground level (by non-sensitive persons, wearing protective clothing) . Dig up the tap root, then destroy it by placing in sealed black garage bag for a few months. Consider leaving vine-tops to die in place. Do not to pull down a vine without serious protection, particularly for the face, eyes, and hands. Wash contaminated clothing separately.

PICTURES FROM THE LEFT: Poison ivy bud just starting to open along the Mill River just north of Tresser Blvd April 2006; a young vine snaking up an ailanthus tree along the Mill River near Cloonan Middle School, Stamford CT April 2006; The whitish-berries on Morgan Street, Stamford CT Nov. 2004.

PICTURE: Poison ivy leafing out in early spring, near Stamford High School, April 2004

For a major infestation, repeated cutting to the ground helps if done consistently. The best way, seriously, is to hire a goat. Alternatively, poison ivy can be smothered (along with everything else) by covering for several months with a foot of mulch, a black plastic trap or the like.

Some horticulturists recommend herbicides. However, the available information on a possible link between lymphoma and others cancers and certain herbicides is disturbing, so why take a chance? If you feel that you must use herbicides, consider the following. In the fall, when the plant is pulling sap down into the roots, first read up on precautions for using pesticides, then buy the smallest possible amount of your chosen product, read the label and do exactly what the label says, except don't use a sprayer. Instead, cut the poison ivy to the ground and very carefully paint each cut stem with the herbicide diluted according to the label. Lastly, carefully follow the law as to proper disposal of any leftover herbicide, contaminated tools and clothing, and your wash-up water.

PICTURES: Poison ivy leafing out in spring, various locations, Stamford April 2005, Note the red color.

PICTURES FROM LEFT: The red poison ivy leaves turn yellowish and soft as they fall to the pavement in the October rain, Hoyt Street Alley, 2004. Detail of one of the fallen leaflets, not looking like poison ivy without its two mates but just as poisonous. A leaf in a hedge along the same alleyway in 2005. Note the "herring bone" pattern of the leaf veins.

PICTURE: poison ivy with THREE leaflets and woodbine (Virginia creeper) with FIVE leaflets. Try to learn to tell the difference.

PICTURE: poison ivy enjoying the fine fall weather at Cove Island, October 2003.

picture: smooth-edged poison ivy leaf	picture: toothed poison ivy leaf
picture: lobed poison ivy leaf	picture: oak-leaf shaped poison ivy leaf

picture: reddish new poison ivy leaf

picture: light yellow-green poison ivy leaf

picture: dark green poison ivy leaf

For more pictures of poison ivy, poison oak and poison sumac,
see the web site of my colleague Walter Muma.

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Photo credits: Sue Sweeney © Sue Sweeney 2006

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