Did you get the bearded iris from me last year? I hope they bloom for you this year. Sounds like they are doing fine though. Sometimes overwinter the rhizomes can heave out of the ground a bit, but I have very rarely lost any from that. Often I just add some soil to it. I only trim when the foliage gets rough looking. Really though, don't worry. My mother in law had learned to cut them back after bloom. Of course, they grew back, so she cut them back again. I know one summer she cut them back 3 times before giving up. They were in too much shade, and mulched. Everything I have heard not to do. They bloomed beautifully every year.