Well, I'm in 5a....so I can really only postulate on *what* I grow, and "where* I grow it....but, here's my 2 cents worth:
I believe that, for you...you should be able to coax bloom from ALL the iris that are known to Re.......from "zone 3'ers", to the "zone 9'ers". I *think* that, besides the lowest average temperature (which is what the USDA zone map tracks), the number of "frost free" days, AND "day length" are important factors in getting rebloom. You should have the "frost free" days, and the "day length" !! As to "needing cold time" in order to bloom, I have heard that the MDB's, and some SDB's don't do well without some
cold time", but, for the "big guys", you should have the perfect climate!!
