Copyright 1998-2017by Yoshiaki Yoneda
Flowers were bred for size and for doubling. At the final stage of the Edo era, when rare attractive flowers were grown, a mutant double flower of Botan (duplicated) was made to mingle with various kinds of flowers. Meanwhile, flower diameters grew larger and larger.
The flower of the morning glory originally was round and small, with a diameter of 5 or 6 cm. The flowers of the varied morning glory of the Edo era were almost this size, but Asagao-hinruizuko (an illustrated monograph of the Japanese morning glory) (1815), depicted a large flower with an ordinary leaf, and the diameter of the flower was around 13 cm. Asagaoso (Varieties of the Japanese morning glory) (1817) depicts a large flower named Higasa (a parasol). This plant has a number of petals, nine stamens, a pistil-like structure, and a flower diameter of about 11 cm. The retracted (suhama or sandy beach) gene is an example of the expanding flower diameter. When this gene is expressed, the center lobe of the leaf is short, the leaf becomes rounded like a sandy beach and the number of petals increases to more than six, and the flower expands greatly. The origin of the retracted gene is still less clear. However, there are figures describing a sandy beach-like leaf in Asagao-36 kasen (36 varieties of the Japanese morning glory) and Ryotisyu (Rare varieties of the Japanese morning glory from two cities) of the Kaei/Ansei eras. If these figures correspond to the retracted gene, then the gene seems to have been born a little before these eras. This retracted gene is a basis of the Higo morning glory, admired as one of six Higo flowers in Kumamoto City. However, the flowers in the Edo era were not so large when we consult the picture books. As for the large-flowered morning glory bred on the basis of the retracted gene, the "Tokoyami" flower, bred in 1886, had a diameter of 15cm, and the horticulturalist Zenkiti Hanai brought up "Sisinden Hall" with a flower diameter of more than 18cm in the thirties of the Meiji era (1897-1906). In those days, a large flower was brought up with a compound cicada leaf. This leaf combined the dragonfly leaf with the retracted leaf. The upbringing of this cicada large leaf established the basis of the large-flowered morning glory, which became the mainstream in morning glory gardening. The large-flowered morning glory includes the Daikoku leaf line, the Ebisu leaf line, etc. The Daikoku leaf is composed of retracted and Globose leaves, while the Ebisu leaf combines the cicada and Globose leaves. A club for the large-flowered morning glory was established in Kyoto in 1886. Gradually, clubs in each region of Japan began to emphasize the culturing of the large-flowered morning glory instead of the varied morning glory. The large-flowered morning glory became the mainstream of morning glory cultivation during the Taisho era (1912-1926). In the Showa era (1926-1989), the Andon method (using the frame of a paper-covered lamp stand) thrived in Osaka. Today, the large-flowered variety is the most cultivated morning glory in Japan. As for methods of cultivating the large-flowered morning glory, each region of Japan has its own characteristics. Besides the Andon method of Osaka, in Tokyo the spiral method and the large-flower pinching method are common, in Nagoya the special pinching method is found, in Kyoto are numerous large-flower-opening methods, and in Higo Kumamoto there is the middle-sized-flower-main-stem method. Huge flowers, of more than 24cm in diameter, bloom currently.
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A lot of commentary books have been published about the large-flowered morning glory. There are many commentary books about morning glories as a whole, including varied morning glories. The main books are described below.
- Miyake, K. and Imai, Y. (1934) Natural-color illustrated Japanese morning glory. Sanseido.
- Nakamura, C. (1961) Japanese morning glory, its culture and blooming method. Seibunndou-Sinkousya.
- Yoneda, Y. and Takenaka, Y. (1981) Natural-color illustrated monograph of Japanese morning glory. Hokuryuukan.