Rhododendron japonicum

(A. Gray) J. V. Suringar

Japanese Azalea, Renge-Tutuzi

Ericaceae Edible: Leaves Potential hazards — see below 301 iNaturalist observations

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Summary

Rhododendron japonicum, the Japanese azalea, is a species of flowering plant in the family Ericaceae, native to Japan. A deciduous shrub reaching 8 ft (2.4 m) but usually half that, it is found in grasslands and open scrub, never in dense thickets or woodlands. It is very similar to the Chinese endemic Rhododendron molle, to the extent that its cultivars are customarily grouped with the cultivars of R. molle. It is popularly cultivated as a bonsai tree.

Description

Deciduous shrub reaching 2 m tall. Hermaphrodite flowers appear April to May, pollinated by insects. Prefers well-drained, mildly to very acid soil in semi-shade or full sun. Tolerates light sandy and medium loamy soils and prefers consistently moist conditions. Hardy to UK zone 5.

Edible Uses

The leaves are reported to be edible, though no further details are given. Caution is advised regarding toxicity.

Medicinal Uses

The plant is used as a diuretic and tonic.

Known Hazards

Caution is advised regarding toxicity of the leaves.

Distribution

It is a temperate plant.

Where It Grows

Asia, Australia, Japan,

Propagation

Sow seed in a greenhouse as soon as it is ripe in autumn, providing artificial light. Alternatively, sow in a lightly shaded part of a warm greenhouse in late winter, or in a cold greenhouse in April. Surface-sow and keep the compost consistently moist. Pot up seedlings once large enough to handle and grow on under glass for at least the first winter. Layering in late July takes 15–24 months. Cuttings of half-ripe wood taken in August and rooted in a frame are difficult.