Cerasus ‘Keio-zakura’

Japanese name: 啓翁桜
Scientific name: Cerasus ‘Keio-zakura’

[Overview]
A cherry cultivar.
A small deciduous tree.
The bark is blackish.
The twigs branch well, and the branch tips spread sideways in a slightly wavy manner, giving a globe-shaped crown.
Aerial roots often emerge from the trunk.
The leaves are alternate and simple, elliptical or obovate, 10 cm long and 5.5 cm wide, with tail-like tips; the upper surface is dark green, glossy and covered with many short hairs, and the underside is slightly whitish with sparse long hairs.
The leaf margins have rounded double serrations.
The leaf stalk is dark reddish purple, with 1–2 nectaries at its upper end.
It flowers before the leaves emerge.
The flowers are borne 2–3 at a time in umbels arising from the leaf axils; they are 5-petaled, about 2 cm across, pale reddish purple, and the petals are broadly ovate to round, 1 cm long, with a large notch splitting the tip in two.
The calyx tube is broadly bell-shaped with hairs at the base, and the calyx lobes are oblong-lanceolate with entire margins and slightly ciliate edges.
The pedicels are densely hairy.
It differs in tree shape from Tokai-zakura, which has the alternative name Keiou-zakura; Tokai-zakura is broom-shaped, while Keio-zakura is globe-shaped, which distinguishes them.

[History]
It is a bud sport obtained by Yoshinaga Keitaro in Kurume, Fukuoka, from a Kohigan-zakura grafted onto a Shinami-zakura rootstock.
Yanaga Taro, a flower researcher, named it Keitaro-zakura after the name of its originator, and it later came to be sold as a cut-flower cultivar under the name Keio-zakura.
Afterwards, a cultivar selected from Keio-zakura seedlings in Takarazuka, Hyogo was sold under the name Keiou-zakura (in honor of the elder Yoshinaga Keitaro), causing confusion over the names.

[Cultivation]
Propagate by cuttings or grafting.
It prefers a sunny, well-drained place.
If it becomes troublesomely large when planted in a garden, it is good to limit the space for the roots to spread with a fabric pot in order to control the size of the tree.
While it is a young tree, protect it from frost by, for example, laying straw around its base.
Also, it is better not to cut the branches needlessly if there is no need.
It is prone to many pests and diseases, so caution is needed.

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