Peonies are long-lived perennials and, if you know how to care for them, they will provide spectacular, showy blooms in late spring for years to come. Good planting and minor maintenance will make your peony a nearly care-free plant and provide plenty of flowers for use in cut arrangements. Poor planting and maintenance, however, can lead to little or no flowering and persistent fungal disease.
For the best flowering, plant your peonies where they’ll get six or more hours of sun. Proper spacing and soil quality are key to preventing problems down the road. Because peonies are sensitive to excess moisture around their roots and foliage, choose a site with fertile, well-drained soil and space plants at least three feet apart to prevent root rot and the development of fungal disease. Amend soil with plenty of good organic matter. To improve cold hardiness, plant so the crown of the plant is about two inches below soil surface; planting peonies too deep will result in lots of foliage but little to no flowering.
Peonies usually require staking to hold up their large, heavy blooms, especially after a rain. Peony rings are easiest to install while plant is still small. Feed plants in spring with a low-nitrogen fertilizer and then again after they’ve bloomed. When more than one bud is present on a single stem, pinching off the smaller of the two will result in a larger flower. Cut peonies in the morning, leaving as much foliage as possible on the plant. Immediately place stems in water. Deadhead any spent flowers left on the plant. If you find discoloration on the leaves, it’s likely a fungal disease. Immediately remove affected portions and don’t compost them. Spraying with a fungicide before bloom can help to prevent disease.
In the fall, cut back stems and dispose of them to prevent over wintering of disease. Mulching will help to protect the roots. Peonies don’t like to be moved or divided, but if it becomes necessary, fall is the best time. Dig up plant and wash away excess soil. Using a sharp, clean knife, cut into divisions containing at least three eyes apiece.