Becky, Munson was in Florida and registered some dormants [he grew all his daylilies under the tall shade of pine trees]. There were also hybridizers in Texas and other southern locations who registered dormants. Hansen in Florida registered a few dormants. Some will be diploids.
If it is possible for you, I would suggest planting dormants in full shade in locations that have hot summers. Arisumi found that daylilies do not grow well at temperatures of 85F and 95F. I suspect that "dormant" daylilies - that is, probably northern bred daylilies, have problems with the high temperatures during southern summers (and perhaps much of the southern year).
