Chysanthemum x rubellium might fit the bill as well. There's a couple of them that are exquiste, one is Mary Stoker
Hardy Chrysanthemum (Chrysanthemum x rubellum 'Mary Stoker')
Mary Stoker may exceed your desired height by 6" as it is about 24" in height.
another might be Clara Curtis
Hardy Chrysanthemum (Chrysanthemum x rubellum 'Clara Curtis')
Bluestone has Mary Stoker for sure, possibly Clara Curtis too, but you'd have to check on the latter suggestion.
