Japanese Azalea
Rhododendron japonicum
- Native to:
- Japan
Photo by David J. Stang
Taxonomy
- Division:
- Magnoliophyta | - Flowering plants
- Family:
- Ericaceae
- Genus:
- Rhododendron
- Species:
- Rhododendron japonicum
- USDA Symbol:
- RHJA2
Growth Characteristics
- Life Cycle:
- Perennial
- Growth Habit:
- Shrub
- Height:
- 300 cm
- Light Requirements:
- Full Sun
- Drought Tolerance:
- Low
- Bloom Months:
- apr,may,jun
- Bloom Colors:
- orange, red, yellow
- Landscaping Shrub:
- Yes
Keystone Species Ranking
- Caterpillar Keystone:
- ★★★★☆ Butterfly & moth species supported by this genus (NWF)
Host Plant for Caterpillars
Io moth (Automeris io)
Garden & Ecology Notes
- Wildlife Value:
- bees, butterflies, hummingbirds
- Fall Color:
- red, orange
Soil Requirements
- Soil Type:
- rich, well-drained loamy soil
- pH:
- 4.5 - 6.0 (acidic)
- Drainage:
- excellent drainage required
- Moisture:
- consistently moist
- Notes:
- prefers organic matter-rich environments
Propagation & Germination
- Stratification:
- Cold/moist stratification required — 60–90 days
- Germination Time:
- 30–60 days
- Notes:
- Seeds require cold stratification for 60-90 days to break dormancy.
ORGHPS Germination Guide: Requires light or the seed is very fine. Surface sow and expose to light. * sprinkle seed on 10 cm damp sphagnum moss; cover with clear plastic pop bottle cut in half; transplant seedling to acidic mix in shade outdoors when 5 cm high; protect from rodents and give protection in cold frame first winter