@caitlinsgarden
I had never heard of dividing this early. I believe the commercial gardens all ship in late August or September. As far as keeping the clump wet, Siberians do want more moisture than bearded, but the time you really want to give more water is before bloom. I wouldn't keep them wet but do water more. You might either use Google for tips for Siberian Iris or go to the American Iris Society website.
