Everyone, please be a little careful looking at the picture on this post; I don't want to be responsible for anyone breaking out in a rash. I'm aware that its not polite in open forum to brag, and I'm sure my karma will be affected for days by even posting this blog publicly, but I happen to be one of those lucky gardeners who seems immune to the evil oils of Poison Ivy (Toxicodendron radicans). "Leaves of three, let it be" is not a mnemonic that I've had a lot of personal use for. Poison ivy immunity is a gift bestowed, in a genetic way, on about 15% of the human population. My mother and, I think, my maternal grandparents were all immune, while my father breaks out at a rash at the mere thought of poison ivy, so in this instance, Thank You Mom. In my garden, I prefer to weed bare-handed, and I pull up random stray poison ivy weedlings, like the one above, frequently with absolutely no ill effects. One summer, as a young boy, I spent a week building a wood fence for my father deep in a pure patch of poison ivy, and for my trouble received about 5-8 little spots of rash by the end of the week. I'm not even sure if they were poison ivy-induced or were mosquito bites. I was thus a dangerous friend to have as a child. Being immune to ivy meant that I could romp at random in the woods and fields near my house without a care in the world about the particular patch of foliage in which I was playing. That also meant that I was accidentally prone to lead more susceptible and less horticulturally aware friends deep into thickets of poison ivy to their detriment.
There are a number of interesting little factoids available out there about poison ivy along with some pretty bad advice for treating or avoiding the skin lesions. None other than Euell Gibbons, he of Stalking the Wild Asparagus fame, recommended eating poison ivy leaves daily for the month of May to build acquired immunity. Yes, that's right, eating three of the tiny leaves (one leaf with three leaflets) while they were still red in color "every day for the month of May." While snake handlers use mithridatism (the practice of inoculating onesself with small amounts of a poison to build up resistance to it) with some success, Euell was promoting a highly dangerous and unproven method for avoiding poison ivy. Don't try it, please.
As a plant, poison ivy can be a vine, groundcover, or a shrub. It is not a true ivy, any more than poison oak (Toxicodendron pubescens) is a true oak. It is related to mango's and cashews, both of which can cause reactions in very susceptible people. The caustic substance produced by the plant is an oil, called urushiol, and there's a lot of information available about the chemistry of the oil if you want to look it up, but I don't see how it's useful to a susceptible gardener to know that the more unsaturated the urushiol molecules are, the greater the bodily reaction invoked. We don't go around with chemistry sets measuring the number of double bonds to decide if we can safely touch a particular specimen.
But, setting all that aside, I'm starting to wonder if a well-cared for specimen wouldn't be a nice horticultural accent to my garden. Just think about it. If poison ivy was a benign plant, the white berries would be coveted by gardeners, and poison ivy is a completely stunning plant in fall when its leaves turn the most wondrous shade of bright scarlet. A large specimen would have the dual purpose of punishing burglars and keeping other interlopers out of my garden, providing privacy for me in my garden as effectively as surrounding the garden with a moat. I think my children are immune, having tested both with a little rub of a leaf in their younger days, but I don't know about my wife. I don't really want to keep her out of my garden, but I suppose it's an option if she gets too uppity about me not mowing the prairie grasses and forbs this year.
