There is nothing dainty about peonies. The colorful flowers can reach 10 inches in diameter, blooming in early summer to herald the upcoming summer season. Peony flowers come in a variety of forms and in nearly every color except blue. Not only are the flowers alluring, the dark green summer foliage provides a great backdrop to other blooming perennials and turns a vivid red in fall. This long-lived perennial (some plants can live 50 to 100 years) can thrive in your garden with little care. No wonder they're called the "King of Flowers" in China.
Types of Peonies
Peonies hail from Asia and have been grown for thousands of years as ornamental, as well as medicinal, plants. But it wasn't until the 18th and 19th centuries that peonies found their way to Europe and eventually America.
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.
Peony flowers are grouped according to shape. Single, semi-double, anemone, Japanese, and double flower forms are the most common. Although peonies only bloom for 1 to 2 weeks in early summer, by planting early-, mid-, and late-season varieties, you can extend the bloom time to four to six weeks.
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 midseason, Fragrant rose-shaped flowers with yellow stamens
'President Lincoln', Single, red, Mid to late season, Large petals
'Sarah Bernhardt', Double rose, Midseason, Rose flowers fringed in pink
'Golden Bowl', Tree Single, yellow, Midseason, 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, Midseason to late, Fragrant, old French variety
In most areas, plant peonies in a full sun location on well-drained soils. Peony roots will rot when planted in poorly drained soil. In hot summer climates, peonies survive best when planted where they receive part shade. The soil pH should be between 6 and 7. Space plants 1 to 5 feet apart, depending on the variety. Locate them away from windy areas but where the air freely flows so it will dry the foliage and help prevent disease. Amend the soil with compost before planting.
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.
Once established, peonies require minimal care. To keep peony flowers from flopping, 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.
Fertilize each spring with compost and a balanced plant food. Keep plants well weeded and mulched. For winter protection, add a 2-inch-thick layer of hay or straw in fall. In cold areas, wrap tree peonies with burlap to prevent winter injury.
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.
For more information about peony growing, contact the American Peony Society Web site at www.americanpeonysociety.org.
Article published on June 23, 2008.