Harbingers of spring, peonies' (Paeonia spp.) large, dramatic and fragrant flowers bloom for only a short time, but their foliage is a welcome addition to the perennial border the rest of the year and turns yellow in fall. Peonies are subject to few pests or diseases and are one of the most reliable bloomers in the perennial garden. If peony flowers cease to bloom there is usually a problem that is easily resolved.
Planted Too Deep
Peonies are propagated by root division. Their palm-like roots are divided into several sections, each with a pink growth point, or "eye." They should be so the eye is just 1 to 2 inches below the surface of the soil, according to Ohio State University Extension.
Loss of Sunlight
With an expected life span of over 50 years, peonies often loose their exposure to direct sun as the years pass and nearby trees reach their mature size. Dig them up and relocate to a spot that receives full sun for at least six hours a day, advises Iowa State University Extension. Although they dislike being moved, (and may not bloom the next season) they will eventually recover and resume their previous level of flower production. Left in a shady spot, they will cease blooming and continue to decline.
Despite the delicate appearance of their blossoms, peony plants are winter hardy, with most varieties surviving winter through U.S. Department of Agriculture plant hardiness zone 2. Their flowers and flower buds though, will succumb to a late-season freeze, according to both the Ohio and Iowa extension services. If this happens, resign yourself to the loss of peony flowers for the current year. The plant will bounce back and bloom again the following spring.