Dave, when I buy Iris from the local lady she digs them while in bloom and puts them in large brown bags for me to take home. No dirt comes with the Iris. It is usually later that day or the next day that I pot them up. I've only lost two Iris in about 4 or 5 years and one of those that was lost was a weak grower anyway. Most continue to bloom too. I think your going to be fine moving them while in bloom.
