Rhododendron wadanum ("Togokumitsubatsutsuji")

Japanese name: トウゴクミツバツツジ （東国三葉躑躅）
Scientific name: Rhododendron wadanum

[Overview]
A deciduous shrub 1.5–3 m tall, found in forests and on ridges in mountains at higher elevations than those where the Pacific-side Mitsuba-tsutsuji grows.
Dense, soft, long, pale brown hairs grow on the young branches, the leaf stalks, and the base of the main vein on the underside of the leaves.
Leaves are simple, borne in threes in a whorl-like arrangement at the branch tips, rhombic-circular to rhombic, 4–7 cm long and 3–5 cm wide.
The leaf stalk is 0.2–0.4 cm long.
It flowers before the leaves unfold or almost at the same time, with 1–2 flowers at the branch tips.
The flowers are reddish purple, 3–4 cm across, and the corolla is funnel-shaped with 5 lobes.
There are dark spots on the inner surface of the upper side of the corolla.
There are 10 stamens.
Dense soft hairs grow on the calyx and flower stalk.
The fruit is a capsule densely covered with long brown hairs.

[Cultivation]
Propagate from seed.
Cuttings are also possible, although the rooting rate is very poor.
It prefers sunny, well-drained, moisture-retentive, fertile acidic soil.
Avoid dry sites, or mulch to keep the base of the plant from drying out.
For potted plants, place them in partial shade out of the afternoon sun and direct summer sunlight from spring to autumn, and in a sunny place sheltered from cold wind from autumn to spring; for plants in the ground, a spot shaded by deciduous trees is good.
For potted plants, water thoroughly when the soil surface dries from autumn to spring, and in midsummer water twice a day, in the cool morning and evening, so that the water also reaches the leaves.
For plants in the ground, rainfall is sufficient except in summer; in summer, water in the cool morning or evening so that the water also reaches the leaves, and in winter, if dry weather continues, water in the morning on a warm day.
Fertilize three times in total, in winter, after flowering as a thank-you fertilizer, and in autumn, applying an organic fertilizer or a slow-release chemical fertilizer with equal amounts of the three components around the plant.
Do not prune; just remove excess buds in early summer after flowering to tidy the shape.
Remove spent flowers promptly.
Pests and diseases include spider mites, azalea lace bugs and Benimon-aoringa.

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