Peonies are an old fashioned easy to grow herbaceous perennial. They require cool winters to fulfill their dormancy requirements. Peonies perform best in well drained loamy soil with good air circulation and plenty of sunshine and spring moisture. If plants do not get enough sun they will not bloom and may even decline in size over time. The best time to divide or transplant peonies is October. This allows plenty of time for root development and nutrient storage before winter. Peonies like a slightly acidic to neutral soil (pH 6.0 to 7.9). To prepare the planting site dig a 2’ wide by 1 ½’ deep hole. If planting more than 1 plant, prepare holes 3’ to 4’ apart. Fill each hole with 1’ of good loam. Each root stock’s crown should be planted 2” below soil level with the eyes pointing up. Finish filling the planting hole and water well. Fertilize peonies in spring and autumn with a low nitrogen product. Too much nitrogen may inhibit flowering. Peonies also like additional potassium.
After foliage dies down in the fall cut stalks back to 1 to 2 inches above soil level. Once the ground has frozen, mulch with sawdust, straw or evergreen boughs. Discard the cuttings as they are not good for composting. If your plant fails to bloom check its soil depth. Usually crowns are too deep, the site has become too shady or there is poor drainage. Botrytis is the most common disease causing buds to die off before opening. Try to keep foliage dry during cool spring weather by watering at the base of plants. Fungicides can be used to control outbreaks. Sometimes plants become overcrowded and will stop blooming. A hard spring frost is enough to kill flower buds. If the crown is too deep, dig the root ball and rework the soil. Replant the root ball ½” above the soil level. Water and mulch well through the summer and the crown should settle to soil level.
Peonies come in 4 flower forms – Single, Semi-double, Double and Japanese (Anemone). Double peonies may not bloom fully their first year depending on the weather. The flowers will become fuller as the plant matures. Peonies make an excellent cut flower. Even after flowering is done the plant provides size and texture in the perennial garden. Peonies also are a Deer resistant plant.