Cut flowers of Herbaceous Peony from Israel
Rina Kamenetsky1, Amalia Barzilay1 and Abraham H. Halevy2
1Agricultural Research Organization, The Volcani Center, Department of Ornamental Horticulture, P.O. Box 6, Bet Dagan 50250, Israel
2 The Hebrew University of Jerusalem Institute of Plant Sciences and Genetics P.O. Box 12, Rehovot 76100, Israel
The peony has long reputation of "queen of the garden" in different countries and continents. In China, peonies were in cultivation 3,000 years ago. The Chinese chose it as the principle flower in the Imperial Palace Gardens, calling it ‘Sho Yo,’ meaning “Most Beautiful”. Missionary Buddhist monks brought knowledge of the Peony to Japan, where, to this day, it is a symbol of prosperity and wealth. By the early 19th century, the peony had been widely introduced into European gardens, and by the 1850's many American nurseries began offering new varieties of herbaceous peonies to their customers. Today, gardeners throughout Europe, Asia and North America regard the peony as one of the most beautiful and most rewarding plants to grow.
The genus Paeonia belongs to the family Paeonaceae and consists of more than 30 species. They are divided into tree and herbaceous peonies. Tree peonies are very popular as garden plants in the USA, Europe, and Russia. These plants grow to eye level on woody stems, their stems staying alive all winter, and then they bloom in the early spring. Herbaceous peonies are more commonly grown, and do well in a wide range of soil types and climates. Their bushy green, pink or red stems grow 80-100 cm tall and each cultivar has leaves of a particular shade of green and a shape ranging from broad to grass-like. Herbaceous peony varieties are primarily derived from Paeonia lactiflora, native to northeast Asia. Flower colors are white, yellow, cream, pink, rose and deep red. The flowers are grouped into types according to the shape of the petal: single, Japanese, anemone, semi-double, bomb and double. They are widely used as garden plants in temperate climate regions, but are less common as cut flowers, in spite of their beauty. One of the reasons for the restricted use of peony as cut flowers is their short flowering season. Cut peony flowers are highly valued in world markets, but they are available for only a short period in late spring and early summer.
Peonies are grown successfully in moderate, cold-winter climatic zones. In the 1980's, the possibility of herbaceous peonies flowering under warmer conditions was reported, and this research gave a start to the development of peony cultivation in Israel. The development of the herbaceous Peony as a new ornamental crop began in Israel 15 years ago from the introduction of a few Peony varieties popular in Europe. It was shown that, under local climatic conditions in the North of Israel, some Peony flower in April-May, and can be exported to Europe as cut flowers. However, we have also learned that, for successful commercial production, Peony has to be subjected to low temperatures during the winter and to moderate-warm temperatures in summer. The rate of vegetative propagation of this plant is rather low, and the propagation process of new prospective varieties takes several years.
To support the rapidly developing branch of Peony cut flower production, several scientific projects have been initiated in Israel in the last few years. One of them focuses on the flowering physiology and optimization of environmental conditions during the dormancy stage and growth. A second project deals with the development of rapid vegetative propagation by conventional methods and in tissue culture. Scientists also studied the possibility of improving and increasing the vase life of the cut flowers, the rate of vegetative propagation, fertigation requirements, etc. The overall aim of these projects is to advance the flowering time of peony and to prolong the marketing period of these cut flowers from Israel.
The information gained in these studies formed the basis for developing three practical methods for cut flower production of herbaceous peonies in Israel:
Growing plants in containers and providing all necessary environmental conditions for optimal flower development. This method requires precise control of the plant development and an in-depth knowledge of the flower's initiation process. With this method a very early crop can be obtained from mid-January on.
Field-grown plants in uncovered greenhouses are exposed to ambient cold temperatures until they receive a certain number of predetermined chill units. They are then covered with plastic sheets, to raise the growing temperatures. This method requires the precise control of temperatures during dormancy breaking and stem elongation. Such plants flower about one month earlier than plants grown in an open field – in March-April.
Peony is grown in open plots and in net-houses for cut flower production in April-May.
The development of new technologies for peony cultivation, in combination with an in-depth knowledge of plant physiology and requirements, brought us to impressive results, and more than two million flower stems were exported from Israel in 2006. High quality cut flowers of the two most popular varieties "Sarah Bernhard" and "Duchesse De Nemours" are produced today on ca. 25 ha. Twenty other varieties, popular in Europe and the USA, have recently been introduced to Israel and are being evaluated under local conditions.
The successful collaboration of growers with researchers and the extension service have allowed for the speedy and effective development of a new and promising branch of ornamental horticulture, which, we believe, will serve as a good example for many new ornamental crops in Israel.
Barzilay, A, Zemah, H, Ran, I. and Kamenetsky, R. (2002) Annual life cycle and floral development of Paeonia ‘Sarah Bernhardt’ in Israel. HortScience, 37(2):300-303
Kamenetsky, R., Barzilay A, Erez, A. and Halevy A.H (2003) Temperature requirements for floral development of herbaceous peony cv. ‘Sarah Bernhardt’. Scientia Horticulturae, 97: 309-320
Halevy, A.H., A. Barzilay and R. Kamenetsky (2005) Flowering Advancement in Herbaceous Peony Proceedings of the IXth International Symposium on Flower Bulbs, Japan, 2004. Acta Horticulturae, 279-286.