I went online to see what I could find about growing dahlias in the South. Apparently there isn't a Florida dahlia society, but I did find the Web site for the Georgia Dahlia Society. It included some great information about dahlias that grow well in the South.
I'm going to join the Georgia Dahlia Society. It's only $27 and you get the newsletter, mentoring from an advanced dahlia grower, $10 in dahlia bucks that you can use at their tuber sales, and much more. What a deal!