In the last two years I think I've culled less then a dozen, so I'm not really too good at it either.
Although Mother nature helped me cull a couple last year. They were just too fussy to start with, and last winter took them, and I didn't replace them. Photogenic, Splurg, and a black one with a tan beard, a Schreiner iris but I can't remember the name. I loved them, but they just didn't do well here even in my micro climate.