Citrus iyo ("Iyokan")

Japanese name: イヨカン （伊予柑）
Scientific name: Citrus iyo

[Overview]
An evergreen tree cultivated as a fruit tree.
Twigs are produced densely.
The alternate leaves look simple, but are actually degenerated compound leaves.
The flowers are borne in short racemes; they are white, 5-petaled and fragrant.
Many stamens are fused up to the middle of the filaments, forming a staminal tube.
The fruit is oblate, weighs 250–300 g, and ripens deep orange.

[History]
It is a chance seedling discovered in 1886 (Meiji 20) by Nakamura Masamichi in present-day Hagi, Yamaguchi.
In 1888 (Meiji 22), Miyoshi Yasunori of Ehime brought it back and propagated it, and it came to be cultivated mainly around Matsuyama.

[Uses]
The fruit is eaten as a fruit.

[Cultivation]
Propagate by grafting.
It prefers a sunny, well-drained location with good water retention.
It dislikes cold, so it is best planted on the south side of a building where it is sheltered from the north wind in winter.
As a home fruit tree, it can be grown outdoors as far as the central and southern Kanto region.
Young trees transplant easily, but mature trees are difficult to transplant.
For plants in the ground, watering is unnecessary unless sunny weather continues and the soil dries out.
In spring and autumn, apply organic fertilizer or a fast-acting chemical fertilizer.
If the branches become too dense and the inside of the crown gets too little sunlight, the branches die.
Dead branches cause pests and diseases and reduce fruit set, so around March prune and thin moderately so that sunlight reaches the inside.
If many fruits set, thin them in July–August.
Pests and diseases include melanose, canker, citrus leafminer, scale insects, spider mites and aphids.
It is a food plant of swallowtail butterfly larvae.

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