There are two basic types of peony plants: herbaceous and tree. Herbaceous, or garden, peonies (Paeonia hybrids) generally grow 1 to 4 feet tall (depending on the variety) and are hardy in USDA zones 3 to 8. In areas with freezing winter temperatures, the foliage dies back to the ground each winter, but the crown and roots survive. In mild climates plants can stay green year-round. Tree peonies (Paeonia suffruticosa) have woody stems and can grow to 6 feet tall. They are also hardy to zone 3, however they may need winter protection to survive in the coldest climates.
Dig a hole 18 inches wide and deep. Plant peonies so the crown (small, colored buds) is only 1 to 2 inches below the soil line. Backfill with soil mixed with compost, and water well. Although you may get a few flowers the first year, it may take 2 to 3 years for a new peony bush to flower fully.
To keep peony flowers from flopping or falling over, stake or cage the plant early in the season. The green foliage will camouflage the cage while keeping the flowers erect. Cut back and compost foliage after a frost. In mild winter areas, reduce watering and remove foliage in fall - even while it's still green - to induce dormancy. If peonies don't go through a dormant period in winter, they will flower poorly the next year.
To produce fewer but larger flowers, remove side buds, leaving only the center or terminal bud to open. Deadhead spent flowers. When cutting peony flowers for display indoors, cut buds before they unfold. Leave two thirds of the plant stem uncut so it will form buds for next year.
If your peonies are healthy, they should flower for years. However, if you notice a reduction in the amount of flowers, you may need to divide the plant. In fall, dig up the clump and separate it into 3 to 5 sections, each with healthy buds, and replant at the same depth in a full sun location.To produce fewer but larger flowers, remove side buds, leaving only the center or terminal bud to open. Deadhead spent flowers. When cutting peony flowers for display indoors, cut buds before they unfold. Leave two thirds of the plant stem uncut so it will form buds for next year.
One of the chief complaints about peonies is lack of flowering. This may be due to lack of sunlight, too much nitrogen fertilizer, overcrowding, competition from other trees and shrubs, planting crowns too deeply, or disease.
Critical to successful peony culture is to spray shoots for botrytis, a grey mold known to attack peony plants. If you encounter botrytis, apply a fungicide spray as soon as the red shoots push through the ground in spring. You may want to re-apply especially if your peonies are closely planted and if there is a wet spring which can cause botrytis to flourish. Taking care with this early culture will pay-off with avoiding black spot, bud blast, and other issues with foliage.
There are hundreds of garden and tree peony varieties available. Some popular peony selections to try are:
Variety/ Flower/ Bloom Time/ Special Features
'Fern Leaf', Double red, Early, Fern leaf foliage
'Festiva Maxima', Double white, Early, White flowers splashed with red
'Nippon Beauty', Japanese, red, Late, Red petals fringed with yellow
'Pink Hawaiian Coral', Semi-double, coral, Early to mid-season, Fragrant rose-shaped flowers with yellow stamens
'President Lincoln', Single, red, Mid to late season, Large petals
'Sarah Bernhardt', Double rose, Mid-season, Rose flowers fringed in pink
'Golden Bowl', Tree Single, yellow, Mid-season, Scarlet flares on yellow petals
'Hana Kisoi', Tree Semi-double, pink, Early, Large cherry pink blooms
'Rimpo' Tree Semi-double, red, Early, Deep red bloom and yellow stamens
'Satin Rouge' Tree Double, red, Mid-season to late, Fragrant, old French variety
Fragrant
Good for cut flowers