With their oversize fragrant blooms herbaceous peonies (Paeonia lactiflora) are among the most glamorous perennials making stunning border plants and cut flowers. Hardy in Zones 3-8, most are long-lived and grow 24-36 inches high and wide. They thrive in cool climates, needing little day-to-day care.
Proper planting is the key to great flowers. For best blooming, choose a site in full sun and well-drained somewhat fertile soil away from the roots of other plants. Set plants about 3 feet apart.
In early fall, dig a hole about 18 inches deep and wide. Mix a 3-inch layer of compost with the soil you removed from the hole. If you are planting a division make sure you can see three to five eyes or buds on the roots. Cover the eyes with an inch of soil to ensure proper blooming. When planting a potted peony, set it in the ground at the same level that it grew in the pot. Typically, when a peony refuses to bloom, it was planted too deep.
Staking may be necessary if your peonies have big, heavy blooms and weak or flexible stems, Position peony hoops available at most nurseries and garden centers when plants emerge from the soil, or set a few wood stakes around the peony, crisscrossing string between them so the peony grows through the resulting web.
Fertilize peonies by giving them bonemeal and wood ash in early summer after blooming.
Diving peonies is seldom necessary. With room to grow, they can stay put for 50 or more years and keep blooming year after year.
Ants like peonies for the sweet nectar they produce, but they don’t hurt the plant. If the ants annoy you, flick them lightly off the flower.