I’ve always been puzzled by the “what’s your favourite” question. How can one choose? That said, the Stinging Nettle, Urtica dioica, could well be my favourite plant. It is probably the one I eat the most, at least in leaf count: some tree-cabbage and kale leaves around here are big enough to cover several hundreds of nettle leaves.
And what’s not to like? Oh, yes, the sting. I kind of like it, or have got used to it.
The mechanism behind this somewhat painful experience lays in the trichomes—tiny hollow bottle-like tubes filled with irritating substances. A nettle trichome may not sound like much, but it is quite a complex structure: the base, a cellular clump, supports a single cell, thin and long—sometimes as long as a centimetre!—that is stiffened with calcium carbonate at its base and silica at its closed tip. This makes the cell very brittle towards the tip, so that it breaks off on contact, whereas the sturdier calcified neck becomes a sharp piercing tool. Through its own chemistry, the bottle becomes a needle!
The cell is filled with a cocktail of substances—all in all up to around 5 nanolitres—that are pressure-injected and help deter many herbivores—not me! Formic acid was believed to be the main irritant, like it is in ants. The long-lasting pain and itch, however, seem to be due to the presence of tartaric and oxalic acid. It is also thought that histamines, acetylcholine, and serotonin, which are all neurotransmitters, contribue to the reaction. But we still know very little about the chemical “weaponry” of the nettle. Somehow, I hope it will long remain a mistery.
One thing I know first hand—and foot, and arm, and knee—is that the stinging power can bring relief to aching joints, and accelerate the healing of deep bruises and strains—I sometimes think the pain from the sting simply acts as a distraction, but hey, its chemicals do seem to help against joint pain. Yeah, the scientific evidence is not mindboggling, but it’s not really a simple experiment (how to apply a placebo or control so that it feels like a sting but it isn’t?). All I can tell you is, it works for me. Given all the neurotransmitters transferred, it’s not very surprising. For instance, acetylcholine is important in the functioning of neuro-muscular junctions, muscles and motor neurons.
It’s often been claimed that Roman soldiers used the “nettle-kiss” method—called urtication—to keep themselves warm and awake, and that it was they who brought nettles to Great Britain—”yeah, that nasty weed? Can’t be native.. probably the Romans brought it”. Nettles lived indeed in most of the Northern hemisphere way before the Romans strolled about. The urtication part may be true, though.
If you get a nasty sting, there is apparently nothing like the juice of—ironically—nettle leaf to cure the rash! And here’s how to handle it: to apply nettle to a nettle rash without causing further rashes, you can simply—haha—”grasp the nettle” from below, with an upwards motion of the hand. Hold the stem bravely—don’t forget to smile—and use the other hand to swipe the leaves and stem in top-wards direction. This should flatten and break the stinging hairs. After a few swipes, roll the leaves either between your fingers or in the safety of a thick cloth. This should—should, I’m not responsible for injuries caused—render the leaves stingless. Now you can crush them and apply them as a poultice. Or eat them, to the delight of children and amazement of adults…
The stinging hairs are just the tip of the iceberg… all of the nettle plant is useful. But I promised myself I would keep this short. So there will be more nettleness coming this way!