Utsugi (Sky tree, Uki, scientific name: Deutzia crenata) is a deciduous shrub of the genus Deutzia of the Hydrangeaceae family. Another name is Unohana. In the Engler system, it may be classified by the family Saxifragaceae.
The Japanese name Utsugi means "empty tree" and is said to be named after the hollow trunk (stem). The flowers bloom in Uzuki (April of the lunar calendar), so they are also called Unohana (Uzuki).
Distribution and growing environment
It is distributed in Japan and China, and in Japan it is widely distributed in southern Hokkaido, Honshu, Shikoku, and Kyushu.
It grows naturally in sunny places such as roadsides in mountains, cliffs, forest edges, river embankments, and remote areas, and is used as hedges in fields or planted in gardens for ornamental purposes.
Form / Ecology
It is a deciduous broad-leaved shrub with a height of 1-2.5 meters (m) and well-branched. The bark is grayish brown to brownish brown, and the old tree splits vertically and peels roughly like strips. The young bark is brown and splits vertically and shallowly. As the branches grow, they lose their pith and become hollow. The bark is grayish brown and peels off as it gets older. The new branches are reddish-brown and have stellate hair.
The shape of the leaves varies widely, changing from an oval oblong shape with a length of 5-12 cm (cm) to an oval lanceolate shape, and opposite with petioles. The leaf blades are thick and stiff with stellate hair.
The flowering season is May-July. Panicles are attached to the tips of the branches, and many white flowers with a diameter of 10-15 mm (mm) are attached together and hang down to bloom. Normally, the petals are five and elongated, but there are also double-flowered flowers. There are 5 long and short stamens, and the filament has wings. Star-shaped hair grows on the calyx.
The fruit season is September-October. The fruits are capsules and have a bowl-like sphere with a diameter of 4-6 mm. A style remains at the tip of the fruit. When ripe in autumn, it splits 3-4 and often remains on the branches even in winter.
The winter buds are opposite to each other and are wrapped in oval-shaped bud scales with stellate hairs, and the branches are also densely populated with stellate hairs. Usually, there are 2 temporary apical buds on the tip of the branch and 8-10 bud scales. The leaf scars on the side of the winter buds are triangular, and there are three vascular scars.
Usage / Culture
It is planted as a garden tree. It is also planted on the shores of fields and used as a landmark for land boundaries. The trunk is processed into wooden nails and used.
Pure white flowers are called "Unohana" and have been loved as a symbol of early summer since ancient times, and have been loved by poetry. In Sei Shonagon's essay "The Pillow Book," there is a story about a group of Sei Shonagon who went to hear the cry of the lesser cuckoo, which is a tradition of early summer like Unohana, folds the branches of Unohana and decorates them in a car. Even in modern times, it is considered to be an early summer tradition as it is sung in the song "Summer is not coming".
The idiom "Unohana rot" refers to the long rain in late May, which means the rain that rots the Utsugi flower. As a seasonal word, it is often used in haiku between "flower rain" and "May rain". The flower language of the bridal wreath is said to be "memories" and "dignity."
There are many varieties besides the variety velvet wreath.
Velvet Deutzia crenata Sieb. Et Zucc. Var. Heterotricha (Rehder) H. Hara
Deutzia crenata Sieb. Et Zucc. F. candidissima (Bon.) H. Hara
Deutzia crenata Sieb. Et Zucc. F. macrocarpa Nakai
Deutzia crenata Sieb. Et Zucc. F. plena (Maxim.) C.K.Schneid.
Deutzia crenata Sieb. Et Zucc. F. Pubescens (Makino) H. Hara
Deutzia crenata Sieb. Et Zucc. F. Purpurina Honda
"Utsugi" of other genera and other family