The Right Place
Peonies can withstand very cold winters and they grow happily as far north as the Canadian border (zone 3). They are hardy in regions where temperatures dip as low as -40°F.
Planting Nursery Stock
Plant peonies in late summer or early fall at least 6 weeks before the ground freezes. A sunny location is best, but they do fine in light shade as well. Since peonies do not like to be disturbed, choose the site carefully. Once established, peonies can stay in place for 15-20 years. A spot that provides some shelter --a wall, fence or building--is desirable to protect heavy peony flowers in bloom from wind. Peonies tolerate a wide range of soil types (pH 6.0 to 7.0) but dislike wet, clayey soils. Because drainage is important, build peony beds higher than the surrounding soil surface or add lots of organic matter (such as chopped leaves, sand, leaf mold, peat moss) to the soil to improve drainage. If possible, loosen the soil 1 foot deep when preparing the bed for planting.
Remarkably adaptable in most things, peonies are very fussy about how deeply they are planted. Set the crown, from which the pointed red buds peak in the fall, an inch or so above the soil surface. Tops of budding shoots must be 1 to 2 inches above the soil surface. Planting too deeply is the most common reason for peonies' failure to bloom. Space plants at least 12 to 18 inches apart. Some experts recommend 3 foot spacing. It takes about 3 years for roots to become fully established and for the plant to begin flowering. Extend the display in your yard over 6 weeks by planting early, mid-season and late varieties.
Plant peonies in tubs or standard clay pots in the spring. Use a good-quality houseplant potting mix --don't use ordinary garden soil.
Amendments In Planting or Transplanting
There are a number of products at the garden center that will help your newly planted or transplanted plants deal better with the stress inherent in the planting process. All healthy plants have beneficial fungi, called mycorrhizal fungi, living on their roots. You can buy these valuable additions to your plant’s ecosystem. See the file describing Using Micorrhizae When Planting.
In addition, there are a number of products such as seaweed, compost tea, and beneficial soil microbes that when added to the planting process will help your newly established plants get going faster. See the file New Technology In Plant Growth Activators