Satsuki azalea Rhododendron indicum
Satsuki azalea (Rhododendron indicum) is an evergreen perennial shrub in the Ericaceae family, native to Japan (Kyushu); the parent of the Satsuki hybrids. It grows 50 cm–1.2 m (20 in–3.9 ft) tall and 60 cm–1.5 m (24 in–4.9 ft) wide, wants part sun to part shade and moderate water, and is hardy to about -15 °C (5 °F). Space plants about 90 cm (35 in) apart.
Plan Satsuki azalea in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Satsuki azalea at a glance
| Type | Perennial shrub, evergreen |
|---|---|
| Family | Ericaceae |
| Mature height | 50 cm–1.2 m (20 in–3.9 ft) |
| Mature spread | 60 cm–1.5 m (24 in–4.9 ft) |
| Spacing | 90 cm (35 in) centre to centre |
| Sun | Part sun to part shade, at least 4 h of direct sun a day |
| Water | Moderate; drought tolerance low, waterlogging tolerance low |
| Soil pH | 4.5–6 |
| Cold hardiness | About -15 °C (5 °F) once established (roughly USDA zone 7) |
| Heat stress | Likely above about 30 °C (86 °F) |
| Flowering | from about May for 2–4 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Low |
| Pollinator value | Moderate |
| Edible | Not grown as food |
| Native to | Japan (Kyushu); the parent of the Satsuki hybrids |
| Common in gardens of | 🇯🇵 Japan, 🇨🇳 China, 🇺🇸 United States, 🇰🇷 South Korea |
Is Satsuki azalea toxic?
- People: moderately toxic
- Cats: severely toxic
- Dogs: severely toxic
- Parts: all parts, nectar
Grayanotoxins in leaves and flowers cause vomiting, weakness and heart rhythm effects.
If a child or pet may have eaten part of a plant, call a poison centre or vet straight away.
Companion planting: what to grow with Satsuki azalea
No well-documented helpful pairing. Group it with plants that like part sun to part shade and moderate water.
Keep apart or take care
- caution With Mountain laurel: Mountain laurel and rhododendrons are hosts of Phytophthora ramorum (sudden oak death), which spreads from infected foliage between neighbouring plants. Evidence B
- caution With English lavender: Acid-loving plants need pH 4.5–5.5, lavender prefers neutral to alkaline soil; one bed cannot suit both. Evidence B
Shared pests and diseases
- Phytophthora ramorum: Sudden oak death pathogen; rhododendron, viburnum, camellia and pieris spread it to oaks and larch. Evidence B
See Satsuki azalea in a botanical garden
It grows in these sample gardens, which you can walk through in 3D:
- The Huntington (18 plants)
- UC Botanical Garden, Berkeley (10 plants)
- Brooklyn Botanic Garden (34 plants)
- The Butchart Gardens (8 plants)
- Fairy Lake Botanical Garden (10 plants)
- Missouri Botanical Garden (14 plants)
- Jardim Botânico do Rio de Janeiro (10 plants)
- Denver Botanic Gardens (8 plants)
- New York Botanical Garden (24 plants)
- Riverside botanical garden (18 plants)
Questions about Satsuki azalea
- How far apart should I plant Satsuki azalea?
- About 90 cm (35 in) apart, centre to centre. A mature plant spreads 60 cm–1.5 m (24 in–4.9 ft).
- Does Satsuki azalea need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Satsuki azalea need?
- Moderate water. Drought tolerance is low and waterlogging tolerance low.
- How cold-hardy is Satsuki azalea?
- It tolerates about -15 °C (5 °F) once established, roughly USDA zone 7.
- When does Satsuki azalea flower?
- From about May for 2–4 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Satsuki azalea poisonous to cats and dogs?
- For cats it is severely toxic; for dogs severely toxic; for people moderately toxic. Grayanotoxins in leaves and flowers cause vomiting, weakness and heart rhythm effects.
- What grows well with Satsuki azalea?
- There is no well-documented companion pairing for Satsuki azalea. Group it with plants that like the same sun (part sun to part shade) and water (moderate).
Sources and evidence
Evidence grade C (C: plausible, mixed evidence).
- RHS Plant Finder, Royal Horticultural Society
- Missouri Botanical Garden Plant Finder, Missouri Botanical Garden
- ASPCA Toxic and Non-Toxic Plant List, ASPCA
Notes and assumptions
- Typical garden-form values; cultivars and local conditions differ.
- Semi-evergreen in cold winters; needs acidic, well-drained soil and shallow roots must not dry out.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
Related plants
- Blueberry Vaccinium corymbosum
- Rhododendron Rhododendron
- American cranberry Vaccinium macrocarpon
- Lingonberry Vaccinium vitis-idaea
- Bilberry Vaccinium myrtillus
- Japanese andromeda (pieris) Pieris japonica
- Heather (ling) Calluna vulgaris
- Mountain laurel Kalmia latifolia