Ragweed | The Canadian Encyclopedia

Article

Ragweed

Ragweed is an annual or perennial plant of the genus Ambrosia, family Compositae or Asteraceae. Fifteen species are native to North America; 3 occur across Canada: common ragweed (A. artemisiifolia), perennial ragweed (A. coronopifolia) and giant ragweed (A. trifida).

Ragweed

Ragweed is an annual or perennial plant of the genus Ambrosia, family Compositae or Asteraceae. Fifteen species are native to North America; 3 occur across Canada: common ragweed (A. artemisiifolia), perennial ragweed (A. coronopifolia) and giant ragweed (A. trifida). Ragweed pollen is the most prevalent cause of hay fever in Canada, and common ragweed can also cause dermatitis. Common ragweed, the most abundant, is an erect, hairy-stemmed, coarse, annual herbaceous plant, 5-200 cm high, usually with deeply divided, dark green leaves. Greenish, male flowers with obvious yellow stamens are borne in clusters along an erect stalk. One-seeded fruits (achenes) occur singly or in clusters, and are found at bases of upper leaves. Ragweed is an abundant weed in cultivated fields, around open disturbed areas and along roadsides, especially in southern Ontario and Québec.

Interested in plants?

External Links

Article
Virus
Article
Violet
Article
Water Lily

Challenge yourself - take the CC Quiz!

The Canadian Encyclopedia is a project of Historica Canada, a non-profit, nonpartisan organization devoted to teaching Canadians more about our shared country.  We also produce the Heritage Minutes and other programs. If you believe all Canadians should have access to free, impartial, fact-checked, regularly updated information about Canada’s history and culture in both official languages, please consider donating today. All donations above $3 will receive a tax receipt.

Book a Speaker