Source: Wikimedia Commons
Kyushu azalea
BeginnerRhododendron kiusianum
A small azalea that carpets volcanic uplands in Kyushu such as Kirishima, Aso and Kuju. With small leaves and dense branching, it covers its shoot tips with little flowers, mostly purple-red but also pink or white. Tough and ideal for shohin bonsai.
About
Rhododendron kiusianum (miyama-kirishima) is a semi-deciduous shrub of the heath family found on high mountains across Kyushu—Kirishima and the Ebino Plateau, Aso, Kuju, Unzen and Tsurumi. In 1909 the botanist Tomitaro Makino saw it at Kirishima and named it 'azalea of the deep mountains'. It dominates slopes disturbed by volcanic activity and is expected to give way as forest returns. Plants grow 1–2 m tall with dense branching; the hairy leaves are small, 8–20 mm, and dimorphic, with spring leaves and smaller summer leaves, some of which overwinter. Funnel-shaped flowers 2–3 cm across open from late May to mid-June in the wild, ranging through purple-red, scarlet, pink and white, with five stamens. Though often sold alongside satsuki, it is a separate species—smaller overall, with even smaller leaves only 8–20 mm long. It is propagated by seed and cuttings, and many cultivars with different flower colours and forms exist. Because most wild populations lie within national parks, plants in the trade should be nursery-grown.
Source: Wikipedia (CC BY-SA 4.0)
Size of the Kyushu azalea
The Kyushu azalea grows to 1–2 m in the wild; often kept around 30 cm in pots.
Basic Info
Origin
Endemic to Japan (high mountains of Kyushu: Kirishima, Aso, Kuju, Unzen and others)
Lifespan
Little data on lifespan
Size
1–2 m in the wild; often kept around 30 cm in pots
Temperature
-5〜35℃
Watering & Fertilizer
Fertilizer (after flowering, plus a winter feed)
Growing Tips
Light & placement
Outdoors in sun and airflow—more sun, more flowers. Soften harsh summer sun with part shade or a screen
Watering
Likes water and dislikes drought, especially while flowering and making new leaves; dryness invites spider mites
Temperature & overwintering
Tough in heat and cold (to about −23 °C / −10 °F). Winter outdoors with proper chill; shelter from harsh drying wind and frost
Soil & repotting
Acidic mix such as kanuma and akadama half and half. Repot young plants every 2–3 years after flowering or in autumn
Fertilizer
Responds well to feeding: after flowering around June and a winter feed around December; add a little in summer if leaves pale
Pruning & styling
Soon after flowering (around May–June) cut new shoots back to about two leaves and remove spent flowers. Crowded growth rots in wet weather
Pests & cautions
Spider mites in dry spells, rot in stuffy conditions. Most wild sites are in national parks where plant collection is restricted—buy nursery-grown plants only
Kyushu azalea FAQ
QWhat is the growing difficulty level for Kyushu azalea?
Beginner. A variety suitable for beginners. No special equipment or experience is required—you can grow it without problems by setting up a basic cultivation environment.
QHow large does Kyushu azalea get?
The mature size of Kyushu azalea is 1–2 m in the wild; often kept around 30 cm in pots. This may vary slightly depending on cultivation environment and individual differences.
QHow should I water and fertilize Kyushu azalea?
Kyushu azalea: watering & fertilizer — Fertilizer (after flowering, plus a winter feed). Aim for appropriate frequency and amount.
QWhat is the typical price for Kyushu azalea?
The price of Kyushu azalea varies significantly by variety, characteristics, size, and lineage. Please check GrowerDirect's price guide for the latest market information.
Last updated: September 23, 2026
References & Sources
Edited & verified by: GrowerDirect Editorial Team
The classifications, regulations, and growing data on this page are created and verified based on the primary information database below.
Taxonomy & Authority
Accepted name: Rhododendron kiusianum Makino
Synonyms: Rhododendron indicum var. japonicum (Maxim.) Makino, Rhododendron kaempferi var. japonicum (Maxim.) Rehder, Rhododendron obtusum var. japonicum (Maxim.) Kitam.
Authority databases: GBIF · GBIF
Nomenclature follows global taxonomic authority databases.
Regulations & Conservation Status
Not listed by CITES and not designated as a Nationally Rare Species. However, most wild sites (Kirishima, Aso, Kuju, Unzen) lie within national parks where collecting plants in special zones is restricted. Choose seed- or cutting-grown plants, never wild-dug ones.
Sources: Species+ (CITES listing search)
Regulations may change. Always verify the latest information with the relevant authorities.
Related Species
Find listings for this species
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