Because your peonies will be in their chosen location for decades, you ll want to prepare the site well. Dig a much larger hole than you think you need, and amend the soil well with well-rotted compost. Peonies are picky this way they do not want to be planted too deeply. If your plants cease flowering after a few years, check to see that they have not sunken too low in their bed or had too much soil accumulate over top of them. Peonies are seen everywhere in the Northeast and Midwest, but can be grown further south.
Climate does affect success, however.
Like lilacs, peonies need a winter chilling period of a certain length in order to set buds. The cold winters and hot summers of the Midwest suit peonies just fine. Gardening Zone 7 is probably the limit of their southern range. Unfortunately, the late-season flowering doubles do poorly in the South. Early-flowering singles are a better choice, even though they are not nearly as showy.