If you go out very often, a discomfort you’re likely to experience is the so-called “seven minute itch.” This results when your bare skin comes into contact with either of the two plant species known as nettles. Both wood nettle (Laportea canadensis) and stinging nettle (Urtica diocea) can cause welts that are reputed to burn no longer than 420 seconds. My skin, however, must be especially susceptible. I frequently have endured an hour or more of intense discomfort (i.e. pain) as a result of not paying attention to where I’m going.
Two remedies seem to help. When near a creek or river, submerging my legs or hands and arms in the water (the colder the better) is one. The other is dousing my skin with Dawn dish detergent, which is also, in my experience, an excellent antidote for exposure to poison ivy. Coal tar also helps.
Wood and stinging nettle belong to the Nettle Family (Urticaceae), which in the southern mountains numbers five species: false nettle, clearweed, Pennsylvania pellitory, wood nettle, and stinging nettle. The first three lack the stinging hairs on their stems and leaves and can’t cause discomfort.
Wood nettle and stinging nettle have the specially adapted hairs that can set you on fire. Stinging hairs, thorns, and similar devices, including the bitter latex contained within many plants, evolved as safeguards against grazing animals. Accordingly, they are designated as “herbivore defenses” by biologists. Other plants like false nettle, clearweed, and Pennsylvania pellitory evolved so as to resemble plants with true defenses, thereby encouraging grazing animals to leave them alone, too.
Each hair on a stinging or wood nettle plant is a small defense mechanism. The hairs contain silica, which makes them stiff. They release a pain-causing substance when their tips are broken off by contact. This tip is a bulb that easily breaks away, leaving a stiff, needle-sharp point coated with formic acids and other pain-inducing substances. In essence, they function as tiny hypodermic needle.
One evening at dusk, I walked down the steps at the far end of our deck to find something I’d left in the yard. As I reached the bottom step, I felt a sharp, hot tingle that turned to a stinging, almost electrically generated pain in my left hand. Then the same sensations occurred in quick succession on the back of my neck, my right elbow, my right calf (I had on shorts), and my right ankle.
My vertical leaping ability never was significant and these days it’s virtually nil. I did manage, however, to spring several feet out into the yard and swat away at the sources of my discomfort, which I had realized by this time were yellow jackets. They’d built a nest in the ground under the bottom step. I could see them swarming angrily in and out of the entrance hole.
I saw that Zeke, one of our German shorthaired pointers (now deceased), was following me. As he reached the top of the stairs, I yelled for him to go back. But he kept on coming and received the full fury of the aroused hive. Somehow or other they knew that his nose and the tender bare spot under the base of his tail were his most vulnerable areas. He knew from previous incidents what to do. He jumped in the creek.
I rubbed away at my stings until the pain subsided. Then I went back on the deck, using another set of steps, went in the house, popped open a cool beverage, and plotted my revenge.