Hi Bob -- I am new to the forum but I have been researching the same subject as I have two 4 ft x 4 ft bunches that are ready to bloom that I need to move. I am no expert and will wait for the PEONISTS to advise but here is an old thread that may help us -- Basically, spring division or moving is dicey and may disrupt blooming or be unsuccessful altogether.

Fall seems best but lets hear from the experts!!

http://forums.gardenweb.com/forums/load/peony/msg0310061322901.html

Yes it is better to move them when dormant, but if you do not have that choice, you can move them anytime. You should expect to pay a price, at least a possibility of no bloom for a year or two. If done with care you should not ever lose a plant. Al