Peonies, like roses, have an ancient pedigree dating back to at least 1000 BC. For centuries, peonies were grown primarily for their seeds, leaves, and roots which were widely used for a variety of ills. The medical value faded in Western cultures as it gained favor with horticulturists, though there is now an renewed interest. Peonies are also a favorite of artists in almost every culture.
Among the many reasons to grow peonies are fragrance and color. Doubles are extremely fragrant whereas single blooms are much lighter. Some have no scent at all. Colors range from white, cream, and ivory through myriad pinks, roses, and dark reds. Several lovely yellows, which are intersectional crosses between herbaceous and tree forms, are also available, though the cost for these rare peonies is high.
Peonies make beautiful cut flowers, though you want to avoid completely denuding your plants, especially when young. Planted at the back of a perennial bed, the deeply cut, glossy green foliage makes a pleasing background throughout the summer for other plants.
Types of peonies
Peonies are available in dozens of varieties including herbaceous and tree forms, The herbaceousPaeonia lactiflora, a native of Siberia, is the Chinese peony with the large, opulent flowers.
Tree peonies (Paeonia suffruticosa) are deciduous shrubs that lose their leaves every fall. They are usually between 3–4 feet tall, but can be shorter or taller depending on the variety. Some can grow as tall as 6 feet.
Paeonia (Peoniaceae) includes woody and herbaceous species, respectively called Mudan and Shaoyao in China. The germplasm is important to the floral and medicinal industries. Although herbaceous peonies traditionally have not been as desirable and popular as endemic tree peonies in China, varieties and hybrids of Chinese origin are increasingly grown around the world for cut-flower production and landscape use (Wister, 1995). Cultivars of herbaceous peonies that originated and were bred in China are nearly all from the speciesP. lactiflora Pall., so even though other species are specific to China (e.g., P. veitchii, P.obovata, P. mairei, P. emodii) (Hong, 2001), P. lactiflora and all its cultivars comprise the plants commonly called the Chinese peony (Wister, 1995). As one of the most ancient crops originating from China, P. lactiflorawas introduced to gardens during the Xia dynasty (1936–1909 B.C.) about 4000 yr ago and become well known before the tree peony became rapidly popularized during the Tang and Song dynasties (619–1279 A.D.) (Cheng, 2007). As an ancient economic crop with splendid floral beauty and an irreplaceable role in Chinese medicine, P. lactiflora has been sustainably developed and selected for desirable traits from generation to generation in China. Today, thousands of its cultivars are widely grown in temperate climates of the world while the species still grows in the wild (Hong, 2001;Wister, 1995).
The germplasm resources of P. lactiflora have brought great changes to peony breeding since being introduced to Europe and America in the 19th century (Wister, 1995). Undoubtedly, P. lactiflora will play a key role in future peony breeding efforts because of its wide ecological adaptation, strong resistance to stress environments, and the variability in flower color and form from the offspring of seeds. Therefore, suitable molecular markers are greatly needed to identify, assess, conserve, and use the germplasm of P. lactiflora, especially those cultivars inherited from ancestors in China where repeated hybridizations over thousands of years and the fluctuating habitats of wild plants have created abundant genetic diversity in the species (Hong, 2001;Wister, 1995). For such an objective, microsatellites or simple sequence repeats (SSRs) have proven to be effective and useful for the study of genetic diversity in crops (Yves et al., 2005) because of their codominance and hypervariability. In Paeonia, however, available SSR markers are relatively limited (Wang et al., 2009; Yuan et al., 2010; Andreas et al., 2010). In this paper, we report the first development of 10 polymorphic microsatellite primers and their characteristics for the Chinese peony, P. lactiflora.
The availability of tree peony varieties in the United States has been considerably limited. For many years, only a few Japanese varieties were available. A few years ago, we encountered some Chinese and Japanese tree peony specialists. They helped us acquire many beautiful varieties that were difficult to obtain in the United States. As we started to collect these beautiful plants, one thing came to mind: “Why not share this pleasure with other flower lovers. We can provide high-quality tree peonies at prices affordable for any enthusiast.” Thus, the “Tree Peony Garden” web site was created.
We have been collecting, and will continue to collect, tree peony varieties. Our goal is to provide large selections of varieties that have thrived in our garden at State College, Pennsylvania. As we successfully obtain and cultivate more varieties, we will introduce them to you.
If you need to plant or transplant your peony, do it in the fall. Grandma used to say that peonies don’t like being transplanted, and that is certainly true of mature plants. If you must move your plant, give your peony plenty of time to develop a strong, vigorous root system before it faces the double stresses of blooming and summer heat. Experts also advise dividing your mature peony rather than trying to transplant it intact. The bonus is two fast growing plants that may bloom the first year after transplant. A plant that is not divided may not bloom for several years.
Let the plant die back in the fall and don’t rush to cut the foliage. After blooming, peonies offer lovely foliage which will allow the roots to store the nutrition it needs for next seasons flowers. Wait until the first hard frost, then cut stems back to the ground.
Peonies are susceptible to fungal infections. The best way to control the problem is to make sure they have good drainage, air circulation, and clean up clippings in the fall so pathogens don’t have a place to live.
Peonies do grow in pots, but are successful only in large, well-draining containers that can accommodate their huge root system. They need to be fed often (once a month) and protected from very cold temperatures. Peonies prefer to be planted in the ground, so your success may vary depending on your diligence.
That said, peonies really need a good cold period of dormancy. Like many other perennial flowers such as lilacs, peonies need not freeze to produce their summer bloom, but being aware of how cold your winters are means you will be able to select the most appropriate peony for your climate.
Each peony variety blooms for only a week or two at the most. To get a more gratifying peony season, choose several varieties with different bloom times.