Herbaceous Peonies

• If peonies are planted too deeply, their shallow roots produce foliage, but no flowers. Plants should be spaced 2 to 3 feet apart. Dig a hole 10 to 12 inches deep--large enough so the roots can spread out in a natural manner--and fill the bottom with aged organic matter, such as peat or compost. Place the plant in the hole, making sure the uppermost buds or eyes will not be covered with more than 2 inches of soil. Then work the soil in around the roots. Cover the hole with remaining soil and water plentifully.
  
  

Tree Peonies

• Tree peonies should be planted 4 to 5 feet apart. According to Cornell Cooperative Extension, tree peonies must be planted more deeply than herbaceous peonies for their roots to form more rapidly and abundantly. Plant the peony so the area of the plant's graft with a rootstock is at least 5 to 6 inches underground.
  
  

Container Grown Peonies

• According to Purdue University Cooperative Extension Service, plant container-grown peonies so the soil surface in the pot matches the soil level in the planting location.