Run-ins with stinging nettle (Urtica dioica) are often itchy, painful experiences thanks to the tiny razor-sharp hooks on the undersides of the plant's leaves. Simply brushing against the plant will cause an itchy rash. Sensitivity to this weed varies from person to person; it sounds as though you're particularly sensitive to it. Stinging nettle is a common roadside weed that grows 3-4 feet tall and has egg-shape light green leaves. A patch of stinging nettle need not prevent you from gardening in your backyard. You can eradicate it with a few simple steps. Mow large stands. Spray remnants of the plants with an herbicide formulated for nettle and other perennial weeds. Follow application instructions on the product label.