Peonies are pretty low maintenance. With your cold zone you should have no trouble with them blooming. 6 hours or so a day of full sun in a non-boggy area is really all they require. They don't like having their roots crowded, keep the grass/weeds pulled around the crowns and they'll reward you with gorgeous flowers for ages. Some varieties need to be divided more often than others and Wes is right, dividing a large clump is VERY labor intensive. You'll know if they need to be divided because you'll get less blooms, typically they'll die out from the middle. Divide/move in the fall if you can. They're actually fairly zeric once established, don't need a lot of water unless the summer gets really hot and they have no shade at all. If you see them droop in the summer just water them at ground level and they'll perk right back up after the sun starts to set. Fertilize if you want after blooming is over with pretty much any fertilizer you like that is for blooming plants or with compost. Those who fertilize their peonies typically do so early spring before there is much growth, but can do so after the flush of growth is over in the summer or in fall, too. Make sure you post pictures when they bloom! Good luck with your peonies!
