I know that Betty
@Betja used to have lots of irises in Bakersfield CA. Not sure what zone that would be. I know that she would pot her irises first to get them growing. That way she could move them out of the intense heat until they were well rooted, and then they could go into the ground later in the season after the temps went down some. I know that she couldn't get the miniature ones to do well there, but she has lots of pictures of her TB's in the data base, so they did well for her.
to the iris forum by the way!