By Roxann Jelinek

University of Minnesota Master Gardener, Brown County

Throughout the course of history few ornamental plants have seen a wider and more varied use than the peony. In the middle ages the peony was prized for its medicinal properties and used as a cure for gall stones, epileptic seizures, and jaundice. Artists used the peony as an inspiration and used the image on porcelains, screen prints, paintings and other works of art. Peonies are the floral symbol of China, the state flower of Indiana, and the 12th wedding anniversary flower. Old saying: You should have peonies in your wedding bouquet because they are regarded as a symbol of good fortune and a happy marriage. The ancient Chinese labeled the peony “king of all flowers.”

The peony is the common name for plants and the only genus of the family Paeoniaceae. Peony plants are native to Asia, southern Europe and western North America.

Today the peony is one of the most popular perennial garden plants as well as a valuable cut flower. There are hundreds of peony varieties on the market, from heirloom favorites that have been enjoyed for centuries, to exciting new colors (peach, coral, yellow), interesting flower forms (spiders, singles and semi-doubles), and different heights and bloom times. The peony comes in every color EXCEPT blue. You might also want to try your hand at growing tree peonies, which bloom earlier than herbaceous peonies. Note: One of the most popular white flowered peonies on the market, ‘Festiva Maxima’ was introduced into the gardening world in 1851. I guess ‘newer is better’ is not always true!

Peonies can be classified by both plant growth habit and flower type. Plant growth types are Herbaceous (nonwoody), Tree (shrub), and Itoh (or “Intersectional”), which is intermediate between herbaceous and tree forms. In winter herbaceous peonies die back to the ground, whereas tree peonies lose their leaves but retain viable woody stems above ground. The Itoh hybrids are intermediate between herbaceous and tree forms. (They are named after Toichi Itoh, who first produced a successful intersectional hybrid in 1948.)

Garden peonies usually are bushy herbaceous perennial plants growing up to three feet in height. Peonies have deeply lobed leaves and delightfully fragrant flowers up to six inches in diameter. Tree peonies are not really trees but grow into small-to-medium sized shrubs that rarely reach more than four to five feet in height in our climate. Intersectional peonies are hybrids and most peonies planted today are hybrids.

The American Peony Society divides flower of herbaceous peonies into four different forms. Single flowers have one row of five or more petals surrounding a cluster of yellow stamens that bear pollen. Semi-double flowers have several rows of petals surrounding pollen-producing stamens that may be in rings or interspersed among the petals. Finally, double flowers have five or more outer (guard) petals with stamens that totally have been transformed into petal-like structures called petaloids. The latter makes up the bulk of the flower. If the guard petals are relatively short when compared with the petaloids, the result is a “bomb” type of double flower.

If a peony is well situated and happy, it may bloom for 100 years or more with little or no attention or a decline in flowering. This means it is worth spending time before you plant to choose the right planting location and preparing the soil. Incorporate well-decomposed organic matter 10 to 12 inches deep in the general area and make individual holes wide enough to spread the roots adequately. You can add fertilizer or bonemeal and mix it well into the soil. Planting depth is very important for good growth and flowering of peony. Shallow planting is preferred since flowering is reduced or inhibited if the eyes are set more than two inches below the surface of the soil.

September is an ideal month to plant or divide peonies. Division should only be done if growth is poor and plants fail to bloom after years of performing well. To divide, lift the clump using a shovel or spading fork. Excess soil should be washed off the roots to reveal reddish color buds or “eyes” (future growing points). The clump then can be divided with a sharp knife or hatchet. Allow at least three eyes per division.

Peonies need plenty of room and should be planted three and four feet apart in a fertile garden loam and full sun exposure. Shade is a key reason peonies fail to flower. Fertilize peonies with care. Excessive amounts of fertilizer (especially nitrogen) can lead to poor flowering. If you decide to fertilize keep the fertilizer 6 to 18 inches away from the crown. Fall application is preferred although early spring is satisfactory. Potassium is essential for stem strength and to resist disease.

Depending on the variety and the growing conditions, you’ll probably want to provide your peonies with some support when the flowers are in bloom. This is especially true for the double or “bomb”-style blossoms, which can become waterlogged and very heavy. The supports should be positioned early in the growing season, before the plants get more than a few inches high. Once the plant has filled out, and especially when it’s in bloom, it is nearly impossible to set up an effective support system.