Urticaceae - nettle family
 

WeedsPoisonous PlantsHay Fever
Gerald A. Mulligan
Research Scientist and Research Institute Director (retired) and presently Honorary Research Associate, Agriculture and Agri-Food Canada,
Ottawa, Ontario K1A 0C6, Canada

Awarded the Lawson Medal by the Canadian Botanical Association in 2006
Read his biography "The Real Weed Man" available in print and ebook.
Laportea canadensis (L.) Weddell, Canada nettle, laportéa du Canada
A rhizomatous perennial, from 1 to 5 feet (3 to 15 dm.) high with very small, greenish, flowers. It is a native plant of moist soils in open deciduous woods, often along seepages and steams. It is found in the eastern half of the United States and Canada. The leaves and stems have a sparse to dense cover of small hairs that can cause an intense burning and itching sensation when they come into contact with the skin. Fortunately, the pain is usually of a very short duration.

Urtica dioica L., stinging nettle, ortie dioïque
It is a perennial herb, 1 to 9 feet (3 to 27 dm.) high. Spread is mainly by shallow creeping rhizomes. Its small, greenish, male and female flowers are in separate clusters on the same plant. It is found throughout our area. Plants growing along stream, river, and lake margins are probably native, whereas plants of roadsides, waste places, and near human habitations are probably introductions from other Continents. Hollow hairs on stems and on the lower surfaces of leaves will fracture easily when touched. This transforms them into sharp hypodermic-like needles that will puncture skin and release a mixture of formic acid and other chemicals that will cause intense pain in humans. This pain, fortunately, is usually of a short duration. Treated in various ways, plant parts are sometimes utilized to produce herbal medicines.

Click on a photo to view an enlarged image.
Weed Name Photo Weed Name Photo
Canada nettle, laportéa du Canada         Canada nettle, laportéa du Canada        
Canada nettle, laportéa du Canada            
stinging nettle, ortie dioïque         stinging nettle, ortie dioïque        
stinging nettle, ortie dioïque          stinging nettle, ortie dioïque
stinging nettle, ortie dioïque
(inflorescence)
stinging nettle, ortie dioïque
(young plant showing stinging hairs)