Rhododendron (genus, "Azarea")

Japanese name: アザレア
Scientific name: Rhododendron

[Overview]
A group of garden cultivars improved for indoor display.
Evergreen shrubs.
They branch freely.
Leaves are simple and alternate, dark green and thick.
Many have large double flowers, and the flower colors are varied: red, purple, pink, white and bicolors.

[History]
From the early 1800s, improvement was carried out in Europe, centered on Belgium, using crosses involving Taiwan-yamatsutsuji and azaleas from Japan and China.
They were introduced to Japan in the first year of the Meiji era.

[Cultivation]
Propagate by cuttings.
It prefers a sunny, well-drained, well-ventilated place.
Avoid dry places, or use mulching or similar to keep the base of the plant from drying out.
Direct summer sun can scorch the leaves, so for potted plants, place them in summer in partial shade out of afternoon sun and direct sunlight, and in winter indoors in a sunny place out of the draft of heaters; for plants in the ground, a spot shaded by deciduous trees is good.
For potted plants, from autumn to spring water thoroughly when the soil surface dries, and in midsummer water twice a day, in the cool morning and evening, wetting the leaves as well.
For plants in the ground, rainfall is sufficient except in summer; in summer, water in the cool morning or evening, wetting the leaves as well, and in winter, if dry weather continues, water in the morning of a warm day.
Apply fertilizer a total of 3 times, in winter, as thanks fertilizer after flowering, and in autumn, using organic fertilizer or a slow-release compound fertilizer with equal parts of the three main nutrients around the plant.
If pruning, do it as soon as possible after flowering, by early summer.
Remove spent flowers promptly.
Pests and diseases include spider mites, lace bugs, leafrollers and Eutelia adulatricoides.

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