Does anyone know who grows Karma dahlias?
Verwer Dahlias in Holland are the originators of the Karma Dahlias. They are protected (breeder's patent), so some countries have few stockists, depending on whether paying plant royalties is common there or not.
Here is a link that might be useful: The Karma range on the Verwer site.
Good place to look first PDSHOP. http://www.dahlias.net/dbiglist.htm