Helianthus petiolaris is part of the Compositae or sunflower family, Asteraceae. This species is commonly known as the prairie sunflower. Naturalist and botanist Thomas Nuttall was the first to described the prairie sunflower in 1821.1 The word petiolaris in Latin means, “having a petiole”.2 It originated in western United States, but has since expanded east. The prairie sunflower is considered a be a weed.
Helianthus petiolaris originated in the dry prairies of Minnesota, Oregon, Texas, California, and other states in western United States. It has since expanded its distribution to throughout the United States and Canada. H. petiolaris is now the most widely distributed species of sunflower besides H. annuus.
The prairie sunflower is commonly found growing in sandy areas. They can also be found in heavy clay soil and in dry prairies. The prairie sunflower is unable to grow in shady areas; it needs to be in direct sunlight. It requires dry to moist soil. This species of sunflower is an annual flower, blooming between the months of June and September. The prairie sunflower can be found from the Great Plains to the Rockies.
This image is derived from a photo taken by Blair Wainman in a rural area approx. 40 kms southeast of Swift Current, Saskatchewan, Canada.
(Info courtesy of Wikipedia)