Peonies should only be transplanted or divided when it becomes absolutely necessary. An established and productive plant may not need dividing for ten to fifteen years or longer.
ive never devided mine and they been in the same spot for 30 years or more, once in a wile ill dig up some to give to a friend, but thats about all. peonies! now i cant wait till spring!
it takes em about 3 years to "settle" i just planted pink peonies last year and dont expect them to flower for another few years so i just plant annuals around em for now,