Prepared by Karen Russ, HGIC Horticulture Specialist, and Bob Polomski Extension Consumer Horticulturist, Clemson University. (New 04/99. Images added 05/09.)
The large showy, flowers of peonies are produced in mid-to late spring. Many colors and flower forms are available. Because winter chilling is required for dormancy, peonies often do not perform well in the lower South. Early blooming and single or Japanese cultivars generally perform better in South Carolina than other types.
'Coral Charm' peony
Wikimedia Commons, Poupon I'quourouce, Creative Commons License 2.5
Most herbaceous peonies grow 2 to 3 feet tall in our area with a 3-to 4-foot spread when mature. Some cultivars and species will grow a foot taller or lower. Tree peonies (which are actually a shrub) grow to about 4 to 5 feet under normal conditions.
Peonies are long-lived, but slow-growing at first. Garden peonies will usually begin blooming within three years after planting. Tree peonies will begin blooming at about the same time, but will increase slowly in size and bloom quantity. They can live for up to a hundred years.
Peonies are grown for their large, showy and fragrant flowers. Most peonies have very attractive foliage that makes them a useful addition to the landscape all season.
Peonies are used as specimens in borders and herbaceous hedges and are excellent cut flowers.
Herbaceous peonies need at least six hours of full sun a day for good bloom. Afternoon shade will protect flowers from fading too quickly in hot areas. Tree peonies should always have dappled or afternoon shade since the large, silky petals are damaged by excess sun. Well-drained, loamy soil is best for good growth of peonies. Good drainage is vital to avoid root rot and fungal diseases. If your soil is heavy clay, amend it with compost, finely ground pine bark or well-rotted manure to improve drainage and organic matter content.
Well-drained, loamy soil is best for good growth of peonies. Good drainage is vital to avoid root rot and fungal diseases. If your soil is heavy clay, amend it with compost, finely ground pine bark or well-rotted manure to improve drainage and organic matter content.
Peonies prefer a pH of 6.5 to 7.0. You may need to add lime to your soil to raise the pH for best growth of peonies. Peonies are long-lived in the garden and are worth extra trouble at the time of planting, since they may stay in the same spot for many years.
Fall planting is best. Dig a hole 12 to 18 inches deep and 12 inches wide. Replace part of the soil in the form of a cone and spread the roots over it. Set the roots so that the tip of the eyes (swollen pink or reddish buds) will be no deeper than 1 inch below the surface of the soil. Most failures to bloom are caused by deep planting.
Tree peonies should also be planted in fall. The graft union should be an inch below ground level. Mound extra soil up around them for the first winter.
Firm the soil in well around the roots, eliminating air pockets. Water thoroughly.
Divisions with three to five eyes will reach maturity sooner than smaller divisions. If one or two eye divisions are used it may be several years before the plant flowers.
Water peonies thoroughly and deeply once every 10 to 14 days. Deep watering will encourage deep rooting. Once established, peonies are very drought-resistant.
Apply a low nitrogen complete fertilizer such as 5-10-5 or 5-10-10 at the rate of two to three pounds per 100 square feet in the spring when the stems are about 2 or 3 inches high. Well-rotted manure may be used to improve the soil if it is applied to the soil surface in a 1-to 2-inch layer. Never let fertilizer or manure touch the stems of the plant.
When you work around the plants in the early spring, be careful of the tender emerging shoots. They will usually be dark red.
Remove seed heads after flowering is finished to allow the plant to store more energy for next year's bloom.
In the fall, after frost, cut back the dead stems of herbaceous peonies down to the soil surface. This is very important if you have had any disease problems. Discard the stems. They should not be used in the compost pile.
NEVER cut back tree peonies. They are shrubs and will not grow back if cut down.
Peonies may be left undisturbed for many years. If you want to divide or move your peonies, do so in late September or October. Carefully lift the clump and wash away the soil to expose the eyes. Using a clean, sharp tool, divide the clump into sections, each with three to five eyes and good roots. Replant immediately.
Most peonies need support to prevent the stems from flopping under the weight of their flowers. Commercial hoops are available for this purpose. You can also use a ring of three or four stakes with loops of tape or plant ties to attach the plants to the stakes for support.
When you cut peonies for the house, pick the flowers in the soft bud stage. They should feel like soft marshmallows. Leave at least 3 leaves per stem on the plant. Recut the stems under warm water and strip off any leaves that would contact water in the vase. The flowers should open within a day of being placed in a vase.
Peonies have few pests or diseases. The most frequently occurring problems are the fungal diseases Botrytis blight and leaf blotch.
Peony leaf blotch
Jody Fetzer, New York Botanical Garden, www.insectimages.org
To help control diseases, cut off all peony plants level with the ground in the fall. Do not add the old tops to your compost pile. Avoid overhead irrigation.
The only insect pests of any consequence on peonies are scales and Japanese beetles.
Ants are attracted to peonies because of the sweet sap the flower buds secrete. It is a myth that ants are necessary to permit peonies to bloom.
A common problem of peonies is the failure to bloom. It may be the result of planting too deeply, immature plants, excess nitrogen, inadequate sunlight, overcrowding, nutrient deficiency, insect or disease problems, competition from roots of nearby plants or late freezes. Some cultivars will fail to bloom in zones 8 and 9 because they lack sufficient winter chilling.
There is a vast array of peony colors and forms to choose from. Most gardeners are familiar with the large, double-flowered peonies. Garden peonies are also available in single-flowered, semi-double, Japanese, and anemone-type blossoms. The single and Japanese bloom types usually perform much better in the South than the doubles do. In addition to the well-known white, pink and magenta flowers, newly available colors include yellow, cream and red.
Tree peonies also come in single, semi-double and double-flowered forms, and the color range includes every color of the rainbow except for blue. Depending on the cultivar and weather conditions, peonies will flower as early as March or as late as May. Tree peonies bloom a week or two earlier than herbaceous peonies.
Early blooming cultivars do best in the South as they have time to bloom before hot weather sets in. They are also less prone to botrytis blight.
Herbaceous Peonies: Modern hybrid peonies are complex crosses of other hybrids and several different species. Paeonia lactiflora is thespecies of many old-fashioned herbaceous hybrids and is often used to refer to them.
'Felix Crousse' peony
The Dow Gardens Archive, Dow Gardens, www.insectimages.org
'Festiva Maxima' peony
Flickr: van swearingen. Creative Commons License 2.0
'Monsieur Jules Elie' peony
Flickr: Tie GuyII, Creative Comons License 2.0
Tree Peonies (Paeonia suffruticosa): Tree peonies form woody branches that do not die back, but simply drop their leaves in the autumn, as does any deciduous shrub. Their flowers are often larger than herbaceous peonies. Tree peonies like the same soil conditions as the herbaceous but require more shelter from the wind, and the larger-flowered varieties will hold their flowers for a longer time if protected from the sun during the hottest part of the day.
Tree peony flowers and plant habit
Wikimedia Commons, Shin- released to common domain.
Fernleaf Peonies (Paeonia tenuifolia): These unusual peonies have finely divided fernlike foliage and deep red single or double flowers. They are dwarf in stature, and bloom very early. They are difficult to propagate and therefore are less available and more expensive.
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This information is supplied with the understanding that no discrimination is intended and no endorsement by the Clemson University Cooperative Extension Service is implied. All recommendations are for South Carolina conditions and may not apply to other areas. Use pesticides only according to the directions on the label. All recommendations for pesticide use are for South Carolina only and were legal at the time of publication, but the status of registration and use patterns are subject to change by action of state and federal regulatory agencies. Follow all directions, precautions and restrictions that are listed.