May 20, 2022

Yamabuki (Yamabuki, scientific name: Kerria japonica) is a deciduous shrub of the Rosaceae genus Yamabuki (a genus of this species only). Another name is Yamaburi. It has yellow flowers that are close to golden. Spring season word.


The etymology of the Japanese name Yamabuki was written as "Yamaburi" in ancient times, and it is said that this was a transliteration. The origin of Yamaburi is said to be associated with the appearance of thin and supple branches swaying in the wind. The Chinese name is called "Tetou". The scientific name comes from Scottish botanist William Kerr.

Distribution / habitat

In Japan, it is distributed in southern Hokkaido, Honshu, Shikoku, and Kyushu, and overseas, it is produced in the Korean Peninsula and China. It grows in clusters along low mountain torrents, on mountain slopes, and in the shade of slightly moist and bright forests. It is a flower that has been popular since ancient times and is often planted in the garden.


It is a deciduous broad-leaved shrub, and although it is a tree, its stems are thin and soft. It is about 1-2 meters (m) tall and stands up, but its tip is slightly tilted and often hangs down to the foot of the mountain. The rhizome is extended laterally and crowded from the root to form a standing stock. The thick part at the base of the trunk is grayish brown and the skin is conspicuous. The young branches are bright green, ridged and smooth, with a slight zigzag. The branches then gradually become woody and brown and die in 3-4 years. The pith in the center of the trunk is spongy and white with a lot of water. The leaves are alternate, obovate, 4-8 cm (cm) long, with distinct heavy serrations on the leaf edges, thin leaf blades, and wrinkled surface. In autumn, the leaves turn yellow and are dyed in bright yellow like flowers, and can be seen until early winter. The flowering season is April-May. Many bright yellow flowers with a diameter of 30-50 mm (mm) are attached to the tips of the current year's branches. There are single and double flowers, and double-flowered varieties (K. japonica f. Plena) are especially preferred and are often cultivated. The single one has 5 petals. There are numerous stamens and 5 to 8 pistils. The carpel ripens and becomes a pistil. The fruit season is September-October. The fruits are wide oval with a length of 4 mm, and it is often thought that the Japanese kerria does not bear fruit, but in reality, the single basic species bears fine fruit. In the case of the cultivar Yaeyamabuki, the pistil is degenerated and the stamens are changed to become petals, so they do not bear fruit. Many of the Japanese kerria that have been cultivated in Japan for a long time are double-flowered seeds that do not bear fruit, so it has come to be said that Japanese kerria does not bear fruit. In winter, leaves fall and green branches can be seen. The winter buds are long-ovate, 4-7 mm long, green, magenta, and 5-12 bud scales, with lateral buds alternating on the branches. There may be side buds on the side. The leaf scars under the lateral buds are semi-circular with three vascular scars.


The remaining varieties are as follows. Yae-Yaeyamabuki (scientific name: Kerria japonica (L.) DC. F. Plena C.K.Schneid.) Variegated Shirahana-Shirobana Yamabuki (Scientific name: Kerria japonica (L.) DC. F. Albescens (Makino ex Koidz.) Ohwi) Kikusaki-Kikuzaki Yamabuki (scientific name: Kerria japonica (L.) DC. F. Stellata (Makino) Ohwi) In addition, Shiroyamabuki (scientific name: Rhodotypos scandens (Thumb.) Makino) seems to be a kind of Yamabuki. Although it tends to be, it is a species of another genus that has nothing to do with Yamabuki. In Japan, it grows only in Okayama prefecture, but it is not uncommon for it to be cultivated in the garden as a flowering tree. There are 4 petals.


The leaves and flowers contain diuretic components and are used as diuretics in Chinese medicine. The flowers are herbal medicines called kerria, which are dried in the sun. People