It's spring. Everything is turning green. Lots of great things for an adventurous dog to do in the backyard. Trees are budding. Bugs to chomp. Maple roots (or canine Pixies Stix as I like to refer to them) to chew and suck on. Birds and squirrels to chase. And delicious Stinging Nettles leaves to munch on.   NOT! Oh, these green leafy innocent looking plants suddenly grow up and tantalize the canine nose, tricking them into coming over and taking a chomp and then seriously regretting it. Now while these plants can be cooked up and are apparently delectable in some recipes (sorry, we'll skip it and just take folks' word for it), the little "stinger" hairs on the leaves and stems that are called "trisomes" and they release  histamine and  acetylcholine, two chemicals which causes a contact dermatitis when touched by people and pets, and it really hurts and burns when touched, which is certainly enough to deter me from tangling with them.  Photo ...