That's tough. Usually right after bloom is great ~~ with zone 5 the upcoming cold nights pose a problem.

Do you have 6 weeks for roots to establish before your first freezes?

Or in spring possibly sacrificing that bloom???

Or right after spring bloom.

Hmmmmmm? Well-----I have 3 JRs in this one area and I think I will experiment with one of them now and wait until after spring bloom to divide the other two.

I do have about the right amount of time to get roots established before freezes in this area. We are in more of a 5b area----that is unless we have an earlier than usual winter. Last year I got a really nice order from Wild Iris Rows in late August but my Mom passed away the first week in Sept. so could not get them planted until I got back home in early Oct. I was pretty concerned about how they would fare but most made it. JR being among those.

Anyway, I appreciate your advice iris gal. Thanks! :)

Aunt Lou