Urtica gracilis (often classified as a subspecies of stinging nettle, Urtica dioica subsp. gracilis) is a widespread nettle species in North America including Canada and Alaska. It has many local names including slender nettle, California nettle and American nettle. This year, my tallest nettle is currently over 2.9m high!
It was (and is) an important plant of the first peoples throughout the continent from Vermont to Alaska,used as a vegetable, medicinally and, most importantly as a fibre plant, including fishing nets!. One native use I noted was “Rubbed on the bodies of sealers to keep them awake at night” :) (Moerman’s Native American Ethnobotany has a long list of uses)
My slender nettle has almost no stinging hairs, and, in general, has much less than stinginess than the introduced Urtica dioica subsp. dioica (stinging nettle) and Laportea canadensis (Wood Nettle; see my book Around the World in 80 plants). It is unisexual ( I seem to have just one sex as it doesn’t produce seeds…)
Added 300917: The friend in Granville, Ohio who sent me the seed of this nettle writes: “I collected the Urtica gracilis along the back of my property, near an old railroad (now a bike trail). It’s a common plant in “waste places”. I’ve never seen the plants grow that large here. Could your additional sunlight be to blame?”