Peonies are hardy herbaceous perennials that grow as far north as U.S. Department of Agriculture zone 2. Any of a few factors may cause peonies growing in full sunlight to produce buds but no blooms.
Dividing peonies into clumps with tubers containing fewer than three to five buds leads to immature plants that may produce no blooms until the tubers grow larger. Planting tubers deeper than 1 to 2 inches can yield the same effect until the roots pull the tubers up in the soil. Self-correction of either problem may take several years.
Too much nitrogen leads to overproduction of leaves; insufficient phosphorus or potassium retards blooms. Trees or shrubs may grow larger over the life of the peony, providing more shade. Insects like aphids may stunt buds. Older crowded plants needing division may bud but not bloom.
Late or sudden spring freezes will stop bud development and the plant will not bloom. Heavy spring rains or an unusually cold and cloudy spring establish conditions favorable to fungal infections and crown rot. The lack of sunlight during such periods may prevent blooms.