Japanese alder (Alnus japonica)
Care, watering, light and tips for Japanese alder on Floravia.
Quick facts
- Family: Betulaceae
- Difficulty: Moderate care
- Watering: every 7 days
- Light: Partial shade
- Temperature: 10–30 °C
About Japanese alder
Alnus japonica, or Japanese Alder, is a medium to large deciduous tree valued for its fast growth and elegant, glossy green foliage. It develops a pyramidal or columnar canopy, making it ideal for street plantings, parks, or as a stately specimen in large gardens, providing attractive vertical structure. Its male and female catkins appear in early spring before the leaves, adding seasonal interest.
Native range
East Asia: Japan, Korea, northeastern China, and the Russian Far East.
Care tips
This alder thrives in full sun to partial shade and prefers moist, well-drained soils, tolerating a wide range of soil types, including poor ones. Watering should be regular during the first few years to establish the tree, keeping the soil consistently moist but not waterlogged; once established, it is quite drought-tolerant. Avoid planting it in excessively dry or compacted soils, as this can limit its development and vigor. It is cold-hardy and does not require complex pruning, beyond removing dead or damaged branches.
How to save a dying Japanese alder
- Warning signs
- Yellowish or brown, wilting leaves; dry, brittle branches. General loss of vigor.
- First aid
- Check drainage and soil moisture. Ensure adequate, consistent watering, avoid waterlogging. Protect from extreme heat.
- What kills it
- Prolonged drought or constant waterlogging, suffocating roots. Exposure to very compacted soils.
- Can it be saved?
- Yes, if you act quickly. Good watering and soil improvement often revive it, if damage isn't irreversible.