A gardener with a peony plant that refuses to bloom may become frustrated trying to determine the cause of the problem. Peonies have specific growing requirements, and if a gardener does not ensure that the peony receives proper care, it may respond with lack of blooms. Get a peony to bloom in a sunny landscape by troubleshooting several different potential situations that may be discouraging peony blossoms, and you may be able to remedy the issue.
Check the planting depth of the peony. If the top of the buds at the base of the plant are deeper than 2 inches beneath the soil, the peony plant is not likely to bloom. A peony plant that is too deep within the soil will put forth standard leaves, but blooms will not form. Remove some soil from above the buds to reduce the amount of soil by scraping the soil away with a shovel or rake. Strive to have between 1 and 2 inches of soil above the buds.
Watch the sunlight exposure on the plant to determine if the peony receives enough direct sun. Peonies need at least 6 hours of full, direct sunlight each day. If a peony receives less than 6 hours of sun and it is not blossoming, lack of direct sunlight may be the culprit. Dig up the peony in the autumn, and move it to a location that receives full sunlight.
Divide a crowded peony if it suddenly stops blooming. Failure to bloom after seasons of successful blooming often indicates a peony that needs dividing. Carefully dig the peony plant from the soil in the autumn, and cut apart a clump so that each division contains between 3 and 5 viable buds. Replant the newly divided peony plants in new sunny locations, placing the buds between 1 and 2 inches beneath the soil.
Survey the planting area to determine if nearby plants or trees may be affecting the peony. Peonies do not bloom well when they grow near walnut trees, because the walnut trees release poisons into the ground. Other trees or shrubs growing nearby may be crowding the peony roots beneath the soil. Consider moving a peony to a different location if you find any of these situations.
Consider the nutritional needs of the peony and how you have fertilized it. If you have provided too much nitrogen, the peony will grow more foliage and may not blossom. If the peony is not receiving the phosphorus and potassium it requires, it may not blossom. Try using a different fertilizer that provides less nitrogen (the first number on a fertilizer tag), more phosphorus (the second number) and more potassium (the third number).
Check for disease that may be affecting bloom. Fungal infections can prevent peonies from blooming and may present with lack of blooms, spots on leaves, decaying stems or wilting foliage. If you notice these symptoms, prune away all infected areas of the peony and discard the foliage. Consider applying a spray fungicide to the peony after removing the infected foliage.