Often found in country gardens, old cemeteries and formal settings, peonies are beloved for their classic charm and bold flowers. Originating in Asia, peonies are widely cultivated throughout the United States and are the Indiana state flower. An herbaceous perennial, the lush, deeply cut leaves of peonies enhance flower beds and borders, while the long-stemmed flowers are ideal for cut flower arrangements and bouquets. Peony flower shapes range from single to double flowering in colors from white to pink and red tones.
Grow peonies in U.S. Department of Agriculture hardiness zones 2 to 8. The plants require a climate with the chill of winter in order to go dormant before emerging again in the spring when warmer weather sets in. Plant new peonies, or transplant your older ones, in late fall as cooler weather arrives. Remove dead leaves and flower stems completely in the autumn for overwintering. This measure reduces the chance of Botrytis blight and Phytophthora blight affecting your peonies, especially in climates with cool, damp mid-summer weather.
Peonies thrive in full sunlight to partial shade. Place a row of peonies along a fence or wall where they receive morning sunlight, yet are shaded from the hot afternoon sun. The plants thrive in the acidic soil near a woodland garden, but should not be planted directly under trees where constant shade will result in failure to bloom. Allow ample room around each peony plant for good air circulation, which will keep the plant healthy and resistant to diseases. A combination of early, mid-summer and late-blooming peony varieties, planted in sunny locations around your property, will provide garden color and cut flowers for nearly two months in the spring and early summer.
Peonies thrive in rich, loamy soil with a pH of 6.0 to 7.5. The plants can live up to 50 years, and as they mature, become less adaptable to being transplanted, so select a permanent planting spot carefully. Prepare the soil by digging a hole 3 feet deep and just as wide, if possible. Layer compost and aged manure with dirt as you backfill the planting hole, creating a long-lasting, nutrient-rich environment for the peony. If you have clay soil, plant the peony rhizomes 1 to 2 inches below the surface. In light sandy soil, the optimal rhizome planting depth is 3 to 4 inches. Each spring, and again in the autumn, apply a 5-10-10 or 10-10-10 formulation fertilizer to the soil surrounding your peony plants.
Keep peony roots moist in the spring as the flower buds mature. Often normal rainfall is sufficient, but if the weather conditions are dry and the top 1/2 inch of soil becomes dry to the touch, run an open hose at the base of the plant to soak the ground. Peonies are drought-tolerant in the summer after blooming, but if dry conditions linger long enough that the leaves begin to droop, water the plants thoroughly. In autumn, when peony roots develop, cover the surrounding ground with mulch to retain moisture in the soil and suppress weeds. Replenish the mulch layer each fall to protect the plants from ground heave that occurs when moisture in the soil freezes and expands.