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Woody peonies are important garden plants in Japan, even though there are no native species. Until the relatively recent arrival of Lutea Hybrids, Japanese gardeners have grown locally-bred cultivars descended entirely from Central Plains varieties brought from China. Selection has been for plants suiting Japanese aesthetic preferences and the local climate. These varieties have made a much greater impact on gardens and peony breeding in Europe and North America than have the Central Plains cultivars.
Woody peonies have been grown in Japan, where they are known as botan, since the Nara Period in the 8th century. They were popular garden plants in the 15th and 16th centuries, when a broad range of Central Plains cultivars was brought to Japan (Cheng 2007). Breeding from that time onwards favoured single or semi-double flowers, rather than full doubles, on longer pedicels than is usual in Central Plains peonies, and held erect. They tend to be later flowering, upright and little branched; they require more accumulated temperature both for bud break and flowering. The Edo Period (1603–1867) was particularly important for breeding around Kyoto and Osaka in the humid subtropical climate of southern Honshu; many cultivars bred then have been lost. More recently, breeding and nursery production has been concentrated in Niigata and Shimane prefectures, on the Sea of Japan coast (Cheng 2007). Hashida (1990) gives a thorough, illustrated account of contemporary cultivars, in Japanese. Burkhardt (2020) provides more accessible web-based information in German and English. Specialist nursery catalogues such as Kelways Plants (2020) and Pivoines Rivière (2020) also valuable sources. We list only a representative selection here.
Numbers of Japanese cultivars were brought to Europe by the German physician and botanist Philipp von Siebold; the date is somewhat hazy due to Siebold’s separation from his plants following his expulsion from Japan on spying charges in 1829, but the peonies were certainly with him in Europe by the 1840s. These included singles and semi-doubles, all grafted on a traditional Japanese, suckering, woody peony rootstock which Siebold named ‘Germania’ (Bean 1976). Grafting is still the norm; these cultivars are not easily divided (Bremer 2019). However, it was later imports from Japanese nurseries in the late-19th and 20th centuries, which established these plants in Europe and North America. It was once commonplace for them to be renamed with European names – a long list credited to Kelway & Son in England from about 1880 probably falls into this category; in any case, the original Japanese cultivars and their names are probably mostly lost (Burkhardt 2020). Poor naming by the exporters did not help: one American writer blamed problems in correctly identifying Japanese tree peony cultivars on ‘the carelessness or unscrupulousness of some Japanese nurserymen. The principle exporters of the 1910–1925 era would sell a collection of fifty varieties with fifty different labels and all but two or three plants would prove identical. The same firm would send fifty plants of one special white variety and the flowers would bloom pink, scarlet, and purple’ (Wister 1962 fide Furman 2020). Several cultivars were selected by William Gratwick of Linwood Gardens, New York, in the mid-20th century; these have been reported as being selected from hundreds of plants raised from seed of Japanese cultivars from the Chugai Nursery, Yamamoto (Armatys 1970; Linwood Gardens 2020). With no other genetic input, these varieties could be considered Japanese botan, which happen to have been raised in America (Cheng 2007), but they do not all unambiguously belong here. ‘Guardian of the Monastery’, for example shows unusually strong P. rockii influence. With both P. delavayi and Gansu cultivars, Japanese cultivars also have been important parents of modern American hybrids (see Lutea Hybrids and Other Hybrids).
Japanese cultivars have generally proved more amenable to cultivation in Europe and parts of North America than the Central Plains varieties. Fertile, well-drained soil, in good light and with good air movement – but not extreme exposure – are general recommendations. They are less tolerant of extreme winter cold or summer drought than are the gansu cultivars. In Japan, discreet support of flowering stems does not seem to be frowned upon in public plantings; ornamental parasols shading the flowers from intense light are also a feature of some Japanese displays.
Winter-flowering woody peonies are a Japanese peculiarity, which has not been replicated in our area; they can be seen in some gardens, protected from snow by little shelters made of a twisted straw mat, open on one side (Ikidane Nippon 2019). Kan botan are specific varieties bred to flower in winter; this behaviour is said to be highly dependent on climate, and even then on correct weather conditions (American Peony Society 2019; Burkhardt 2020). Fuyu botan are conventional varieties kept artificially dormant in spring and summer, then forced under glass in autumn, to flower outdoors in winter (American Peony Society 2019).
Clear pink with a small red-purple flare; large (to 25 cm) semi-double; height to 1.2 m. Selected by Gratwick, 1959, from Japanese seed. (American Peony Society 2020; Pivoines Rivière 2020; Solaris Farms 2020)
Semi-double with ruffled petals opening from tulip-shaped buds, bright rose-pink, the stamens clearly visible; late flowering, to 1.2 m tall; stems and petioles red. A late 19th century Kelway’s introduction, thought to be a renamed Japanese cultivar (Burkhardt 2020; Kelways Plants 2020).
Very large semi-double flowers (exceptionally to 30 cm across) with ruffled petals, light pink, deeper towards the centre, the stamens clearly visible; mid to late season, to 1.2 m tall. An 1897 Kelway’s introduction, probably a renamed Japanese cultivar, still relatively widely grown in Britain (American Peony Society 2020; Burkhardt 2020; Kelways Plants 2020).
Paeonia Japanese Cultivars 'Fuso-no-tsusaka'
Paeonia Japanese Cultivars 'Gekkyu-den'
Paeonia Japanese Cultivars 'Mrs William Kelway'
Pure white semi-double, the yellow stamens clearly visible; flower to 22 cm diameter. A Japanese variety, probably very old, and well known in both Europe and North America (American Peony Society 2020; Burkhardt 2020; Cricket Hill Garden 2020; Pivoines Rivière 2020). ‘Mrs William Kelway’, introduced 1892 by Kelway & Son and quite widely grown in Britain, has long been presumed to be a renamed Japanese variety; Kelways themselves now consider this to have been ‘Godaishu’ (Kelways Plants 2020; A. Martin, pers. comm. 2020).
White, increasingly flushed purple-pink towards the conspicuous dark purple flares; open semi-double to 20 cm across; tall (to 1.5 m) and vigorous. Selected by Gratwick, registered 1959 (American Peony Society 2020; Pivoines Rivière 2020); although claimed as being grown from Japanese nursery seed, it is often considered a hybrid with a Gansu Cultivar / P. rockii (Solaris Farms 2020).
Paeonia Japanese Cultivars Floral Rivalry
Clear pink, sometimes silvery towards margins; a very large flowered (to 25 cm diameter), erect, semidouble. Raised in Osaka before 1929; widely grown and praised outside Japan (American Peony Society 2020; Burkhardt 2020; Pivoines Rivière 2020).
Paeonia Japanese Cultivars 'Kaow'
Rosy red, ageing lighter; very large flowers, to 23 cm diameter; unusually for Japanese cultivars, flowers on strong shoots are almost full doubles. Introduced by C. Watanabe, Shimane Prefecture, 1931. The name translates as ‘King of Flowers’. It is quite widely offered on both sides of the Atlantic. (Burkhardt 2020; Pivoines Rivière 2020)
Paeonia Japanese Cultivars A Murder of Crows
Paeonia Japanese Cultivars Flight of Cranes
Pure white with yellow stamens; a large (to 23 cm across) semi-double, opening flat; foliage purple tinted. Bred in Osaka before 1889. (American Peony Society 2020; Burkhardt 2020; Pivoines Rivière 2020)
Paeonia Japanese Cultivars 'Shima Daijin'
Paeonia Japanese Cultivars Island Minister
Reddish-purple; a rather full semi-double with ruffled petals; flowers to 20 cm diameter; vigorous. Raised by K. Ikeuchi, Shimane Prefecture, Japan, 1952. Widely available in Europe and North America. (Burkhardt 2020; Pivoines Rivière 2020)