Barbara Pleasant is a garden writer and MOTHER EARTH NEWS contributor.
http://www.barbarapleasant.com...
this article is somewhat dated, Harry Huff of Huff's Garden Mums and Vincent Dooley from MN have probably not been active for 10 years or more. Mums of Minnesota (
https://www.fgimn.com) carries some of Dooley's introductions. Company name is Faribault Growers.
G.H. Wild seems to carry about a half dozen mums from Mums of Minnesota, clearly the stock photos are from Faribault...
https://www.gilberthwild.com/p...
Bluestone Perennials has a large selection of mums...
https://www.bluestoneperennial...
The University of Minnesota had a breeding program that started in the 1930s that produced many Chrysanthemums for colder climates...
https://www.maes.umn.edu/publi...
Also, the MAMMOTH mums series was developed by the University of Minnesota,
http://krismers.com/WebPages20...
the Yoder Brothers (the largest producer of chrysanthemums in the U.S.) seem to sell most of the "florist" type chrysanthemums (not hardy). They are a wholesale company. I assume that the majority of their products are sold at the fall mum sales at your local nursery or grocery store.
As far as the National Chrysanthemum Society goes, I think "show" chrysanthemums refer to the fancy "greenhouse" mums, not to something you would grow in your garden.