Urtica dioica (Stinging Nettle)
Family:
Urticaceae (Nettle)
  
Leaves and stems of Urtica dioica have hairs that cause a strong stinging sensation when touched. Leaves are opposite with toothed margins. Spikes of small, green flowers grow from leaf axils. Plants are 3 to 5 feet tall and grow in moist areas along streams and ditches.

Vegetation zone:  Foothills, Montane
Time of bloom:  June - September
Origin:  Native
Eastern Colorado Wildflowers