Echinacea Production in Manitoba

I live in Manitoba and I am doing a project on echinacea production. I understand that the angustifolia is native to Manitoba but it is the hardest to grow; can you explain why? Also we have clay soil; could this plant or purpurea be grown successfully here?

Echinacea angustifolia is a bit slower to grow and somewhat harder to germinate than E. purpurea. Both are hardy in Manitoba, but purpurea does better in wetter conditions than angustifolia. There are other crop production and marketing differences that are outlined in our ebook. "Echinacea 2000: Technical Crop Report" by Richard Alan Miller. For more information on the ebook, please see:
www.richters.com/Web_store/web_store.cgi?product=XB4670-002