Some plants are a mere “flash in the pan,” appearing at nurseries for a season, only to vanish from shelves and catalogues, never to be seen again. Other plants are perennial favorites, relished not only by us and our parents, but also by our grandparents and their parents before them! Peony, botanically named Paeonia is one such timeless beauty. I vividly remember the Peonies that lined my grandparents’ driveway, and as I was contemplating a design last summer at Rutgers Gardens, that memory served as the inspiration for the new planting.
Paeonia is the sole member of the family Paeoniaceae, which features around 33 species native to Asia, Europe, and Western North America. The Swedish botanist, Carl Linnaeus (1707-1778) officially ascribed the genus name to the plant in 1753. Rooted in Greek mythology, Paeon was the physician of the Greek gods and, as the story is told, he was responsible for discovering the medicinal qualities of Peonies. Paeonia officinalis is the type or model Peony by which all the other species are compared. Also described by Linnaeus in 1753, it is native to France, Germany and Italy, and was well renowned for its curative properties. In fact, its root had been used for well over 2,000 years in the treatment of epilepsy and uncontrollable convulsions. The species epithet of officinalis was a term that Linnaeus originally coined in 1735 and used repeatedly throughout his career. It stems from the Latin officina, which initially meant workshop or place of work. Later, it transitioned to the name of a storage room in monasteries where medicines and medicinal plants were stored. Officinalis means “belonging to an Officina” and Linnaeus affixed this epithet to plants or animals that were known to have medicinal benefits. In a similar vein, the Chinese native Paeonia lactiflora was a staple in ancient Chinese medicine for reducing inflammation and arthritis. Once again, it was described by Linnaeus in 1753 and is a species with many garden worthy selections,
Clearly, Peonies are best known for their fragrant flowers and Paeonia lactiflora is certainly responsible for a good number of selections. The species epithet literally means milk-white flower, but the blooms also come in pink, red and bicolor forms. Adding to the dizzying array of colors are the number of forms available, with the flowers broken into six categories, based upon the arrangement of the petals, stamens and carpels. Stamens are the pollen-generating portion of the flower, consisting of the anther and their supporting stem or filament, while the carpel is the seed-yielding organ, consisting of the pollen receiving stigma and ovary. Lured by the promise of fuller flowers, the double flowered forms are the most popular with gardeners. With these selections, the anthers have become petaloid, meaning they have assumed the appearance of a petal. The resulting flower is large, billowy and far too heavy for the stem to support, especially during heavy rains when the stems collapse under the floral weight. As a child, I took great delight in running the lawnmower over flowers laying in harm’s way as the resulting shower of petals shooting forth from the mower deck was ever so colorful! Somehow, my mother never shared my glee. The plants can be staked to reduce the impact of the weather, but the flowers still tend to hand down or dangle over any supporting string or wire mesh. With time, I came to the realization that the single flower, which feature 1-2 rows of petals and a central boss of yellow anthers were just as attractive and far more weather tolerant. The remaining four classes of “Japanese,” “Anemone,” “Semi-double,” and “Bomb” feature stamens that are either slightly fattened as in the Japanese category to narrow petaloid in the Bomb series. Certainly more than enough variety for a gardener to choose a favorite! One of the other fascinating properties of Peony flowers are the extrafloral nectaries. Nectaries contain sugar rich fluids intended to attract pollinators. On Peonies, the nectaries are also located on the calyx or leafy bracts that surround the flower bud, with the intended purpose of attracting ants! As one knows, ants never appear one at a time, but in teams! Although this trait that may not appeal to many gardeners, the team of ants actually serve to protect the flower and their food source from insects that could potentially damage the flower bud or flower! Simply genius!
Most Peonies grow to 24-48 inches tall and are herbaceous, dying to the ground in late autumn. The 8-12” long by 4-6” wide foliage is compound, with each leaf consisting of several small leaflets appearing along a central stem or rachis. The 9 leaflets are a glossy, dark green in color and are typically deeply lobbed. However, there are always exceptions, such as Paeonia tenuifolia. Named again by Linnaeus, the name comes from the Latin Tenuis, meaning thin, fine or slender, which aptly describes the leaflets as they are very narrow and much reduced in size, giving the plant a very lacy appearance. In regions with high humidity or poor air circulation, Peony leaves often develop powdery mildew in late summer. Come fall, plants can develop an attractive, deep red fall color, especially if located in full sun. Come December, the stems can be cut back to the ground.
Paeonia suffruticosa, commonly known as Tree Peony, is another anomaly in this family, since it develops into a woody shrub, growing upwards of 4-6’ tall and wide. Native to China and capable of living to over 100 years of age, the woody stems allow the plant to nicely display the large 4-8” diameter flowers without the flowers drooping or ending up on the ground. In 1948, after countless attempts, the Japanese horticulturist Toichi Itoh successfully crossed the yellow ‘Alice Harding’ Tree Peony with the peach colored P. lactiflora ‘Katoden’ and created the Intersectional Peonies, otherwise known as the Itoh Peonies. Oddly, the series did not gather much notoriety in the US until over 60 years later when several major nurseries finally began to promote and offer the plants for sale. They feature stems that stretch to 36” tall and are woody towards the base yet fleshy near the top, combining the traits of both parents. The stems annually die back to the woody part of the stems and it is often tricky to determine where to trim the stems each spring. If you cut the stems back too far, the flowers buds are also sacrificed for that year, so it is best to wait until new growth begins before removing any dead material. The foliage is glossy green with red highlights and the lightly fragrant flowers are typically semi-double in colors ranging from yellow, to apricot and pink. The flowers appear throughout the month of May into June and are well supported by the stems.
Most species prefer a full sun location in well-drained soils. Two exceptions are Paeonia japonica and Paeonia obovata, which prefer shade. They both have rather unremarkable single white and pink flowers respectively, but the interest is actually comes in late summer when the seed pods split open; the seeds are deep purple, which contrasts nicely with the supporting bright red stems, connecting them to the seed pod. Very striking! Although Peonies rarely require division, the thick tuberous roots are best lifted and separated in late August or early September if division is desired. When replanting the roots, make certain that the large ‘eyes’ or buds for the ensuing year’s stems are located within 1” of the surface. If they are located too deep or mulched too heavily, the plant will fail to flower in the future.
Clearly, the various species of Peony provide solutions for many design challenges that a gardener may face. Deer resistant, low maintenance needs, attractive flowers with nice fragrance and good overall structure, it is clear to see why this plant has remained popular for so many generations. Hopefully generations to come will continue to appreciate this plant, allowing more burgeoning young gardeners to aim their lawnmowers at collapsed flowers and begin their humble path to becoming a gardener!