Rhododendron yakushimanum
Rhododendron yakushimanum · Ericaceae
📷 As6022014 · CC BY-SA 4.0
⚠️ Feuilles et fleurs contiennent des grayanotoxines ; leur ingestion peut provoquer salivation, vomissements, faiblesse et troubles cardiaques chez chiens et chats.
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around rhododendron yakushimanum and prepare for winter.
ID card
- Foliage
- Evergreen, dark green, covered with a fine reddish indumentum
- Flowering
- April to May, pale pink to white flowers in compact clusters
- Adult size
- 1.50 m in height, 1.20 to 1.50 m in width
- Growth
- Slow to moderate
- Hardiness
- Excellent, down to -15 °C
- Origin
- Yakushima Island, Japan
- Soil type
- Acidic, well-draining, rich in organic matter
✓ Taxonomy verifiedSource: AI estimate · hardiness: reliability high.
Expert tips
The key tip
Plant shallowly in acidic, well-draining soil: this excellent compact rhodo roots quickly when conditions are right. Annual peaty mulch is enough to keep fertility up.
The common mistake
Most gardeners think rhodo = heavy feeding: on this super-compact nano-rhodo, too much fertilizer triggers messy growth and hardly any flowers.
The pro's trick
Don't prune for the sake of it: this rhodo naturally grows dense and well-shaped.
Care
Watering
Keep the soil moist but not waterlogged, especially during active growth and flowering. In dry periods, water regularly in the morning using non-limey water. Reduce watering in winter, but don't let the substrate dry out completely. Mulching helps retain moisture.
Exposure
Plant in partial shade, protected from midday sun which can scorch the foliage. A location with dappled morning light and afternoon shade is ideal. Avoid areas exposed to drying winds or salt spray.
Soil
Require acidic soil (pH 4.5 to 6) and very well-draining. Enrich the soil with heather soil, peat, or leaf compost to ensure good root aeration. Install effective drainage to prevent root asphyxia in case of excess water.
Pruning and structure
Light pruning after flowering (June) helps maintain a compact shape and remove spent flowers. Remove dead or misplaced branches. Generally, this rhododendron branches naturally and requires little intervention.
Fertilizing
Apply a rhododendron-specific fertilizer in spring, before flowering. Use a balanced product that is slightly acidic. Additional feeding in June after flowering promotes the formation of flower buds for the following year. Avoid excess nitrogen.
Diseases and pests
Watch for powdery mildew in case of stagnant humidity: improve air circulation and reduce foliar watering. Scale insects can sometimes settle on the leaves. Overall, this variety is robust; good hygiene and appropriate growing conditions prevent most problems.
Did you know?
Rhododendron yakushimanum originates from the mountains of Yakushima Island in Japan, where it grows naturally at altitude in extreme conditions. Its exceptional hardiness and compact habit made it very popular with hybridizers, who used it to create many new cultivars. In 1976, this species was designated the official flower of Kagoshima Prefecture in Japan.
Where to buy it
Best planted in autumn so the roots settle in before summer, or in early spring once the frost has passed. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, October, November.
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Tips generated and checked by Viridia — adapt them to your local climate.