Peonies are incredibly popular and require very little care over time. They hate to be moved and if given the proper conditions will flower beautifully for 100 years in the same spot. Take the time to prepare an excellent planting site that will supply your peonies with everything they need to flower for years and years and you won’t regret it.
Peonies need at least six hours of direct sunlight each day. Peonies in shaded areas will not flower well, if they flower at all. The exception to this rule is for plants grown in very warm climates, such as hardiness zones 7 and 8. Those peonies should have access to protection from the hot afternoon sun; the east side of a house is a good location. The only other acceptable type of shade, according to professional peony grower La Pivoinerie d’Aoust Peony Nursery, is shade from high, light foliage.
Peonies are heavy feeders. Take plenty of time to prepare the soil before planting by adding compost or well-rotted manure. Dig a hole that is 12 to 18 inches deep and loosen the soil on all sides, adding compost as you loosen. Build a small pile or cone in the middle and place the bare-root peony on top of the pile so its roots have plenty of loose, fertile soil to penetrate. Apply a granular fertilizer around the base of the peony every spring for sandy soils.
Standing water will cause your peonies to rot. If you have doubts about your soil’s drainage, dig a hole and fill it with water. If the water remains after a few hours, choose another site. Heavy soils can be amended with compost to loosen them up ad improve drainage.
If you notice that your peonies have stopped flowering as much, year after year, it’s probably time to divide them. Division will rejuvenate the peonies and get them producing gorgeous flowers again. Divide plants in the fall and plant them at the same time. When you dig up the mature root system, expect it to be large. Make divisions by cutting the root system into divisions with a balanced number of roots and new buds. New buds are pink, located at the top of the root system–the crown–and are also called eyes. There should be three to five eyes per division. Plant the divisions so the topmost eye is no more than 2 inches deep.
Air circulation is integral to protecting peonies from their only disease threat, botrytis. Botrytis is a fungal infection that kills buds and foliage and rots the roots and base of the plant. Botrytis is naturally present in soils, but wet, cool weather renders plants more susceptible because it stresses them, so give peonies an advantage against the disease by spacing them properly. Peonies grow to a height of 2 to 4 feet and 4 to 6 feet wide. Plant peonies at least 2 feet apart.