Herbaceous peonies do best in zones 2-8. Plant roots no deeper than 1" below the soil surface, watering only as needed. Peonies will begin to die back in August in preparation for a period of needed dormancy. Remove foliage from garden area to avoid disease problems. .
UPON RECEIPT OF YOUR PEONIES
Inspect peony roots carefully when you receive them. If they appear dry, soak in water for 4 hours. If they cannot be planted soon, repack them in the packing material and wet thoroughly, leaving in a dark, cool place. They will keep for a week or two without damage.
Select a sunny, well-drained location with good, well-drained, soil. Dig a hole large enough to accommodate the root system. Plant peonies 2" below the soil surface with the eyes facing upwards. Fill the hole with soil and a good compost, water thoroughly. For the first winter, apply a 3 to 4 inch layer of loose mulch. This is especially important in the North or with late-season planting. Pull mulch back in the spring, away from new shoots. Once peonies are established, winter mulch is not needed. The ideal transplant time is anytime during the fall when the ground is not frozen.
Peonies should not be over-fertilized. Bone meal is a good fertilizer, but any complete garden fertilizer not too rich in nitrogen is ideal. Best time to fertilize is early summer, after peonies have bloomed and been deadheaded. They will be developing new eyes for the next season at this time. Once every several years an application of a well-balanced, slow-release fertilizer is adequate. Generous amounts of fertilizer can be detrimental to peonies. In severe cases of over-fertilization, the entire plant may be burned. Less severe consequences may be fewer blooms, no blooms or spindly growth.
Peonies bloom late-May through early-July in our southern Ontario climate, which is in zone 5. Depending on your zone, they will bloom within a few weeks of this in Spring.