Alpenrose (rusty-leaved alpenrose) Rhododendron ferrugineum
Alpenrose (rusty-leaved alpenrose) (Rhododendron ferrugineum) is an evergreen perennial shrub in the Ericaceae family, native to Acid soils of the Alps, Pyrenees, Jura and northern Apennines, above about 1,500 m. It grows 50 cm–1.2 m (20 in–3.9 ft) tall and 80 cm–1.5 m (31 in–4.9 ft) wide, wants part sun to part shade and moderate water, and is hardy to about -32 °C (-26 °F). Space plants about 1 m (3.3 ft) apart.
Plan Alpenrose (rusty-leaved alpenrose) in your garden →
Free. Draw your beds, then watch it grow through the year in 2D and 3D.
Alpenrose (rusty-leaved alpenrose) at a glance
| Type | Perennial shrub, evergreen |
|---|---|
| Family | Ericaceae |
| Mature height | 50 cm–1.2 m (20 in–3.9 ft) |
| Mature spread | 80 cm–1.5 m (31 in–4.9 ft) |
| Spacing | 1 m (3.3 ft) 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 none |
| Soil pH | 4–6 |
| Cold hardiness | About -32 °C (-26 °F) once established (roughly USDA zone 4) |
| Heat stress | Likely above about 26 °C (79 °F) |
| Flowering | from about June for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones) |
| Wind tolerance | Moderate |
| Pollinator value | High |
| Edible | Not grown as food |
| Native to | Acid soils of the Alps, Pyrenees, Jura and northern Apennines, above about 1,500 m |
| Common in gardens of | 🇩🇪 Germany, 🇫🇷 France, 🇮🇹 Italy, 🇬🇧 United Kingdom |
Is Alpenrose (rusty-leaved alpenrose) toxic?
- People: moderately toxic
- Cats: severely toxic
- Dogs: severely toxic
- Parts: leaves, flowers
Like other rhododendrons it contains grayanotoxins: dangerous to grazing animals and pets.
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 Alpenrose (rusty-leaved alpenrose)
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
Questions about Alpenrose (rusty-leaved alpenrose)
- How far apart should I plant Alpenrose (rusty-leaved alpenrose)?
- About 1 m (3.3 ft) apart, centre to centre. A mature plant spreads 80 cm–1.5 m (31 in–4.9 ft).
- Does Alpenrose (rusty-leaved alpenrose) need full sun?
- Part sun to part shade: at least 4 hours of direct sun a day.
- How much water does Alpenrose (rusty-leaved alpenrose) need?
- Moderate water. Drought tolerance is low and waterlogging tolerance none.
- How cold-hardy is Alpenrose (rusty-leaved alpenrose)?
- It tolerates about -32 °C (-26 °F) once established, roughly USDA zone 4.
- When does Alpenrose (rusty-leaved alpenrose) flower?
- From about June for 4–6 weeks (northern hemisphere; later in cold climates, earlier in warm ones).
- Is Alpenrose (rusty-leaved alpenrose) poisonous to cats and dogs?
- For cats it is severely toxic; for dogs severely toxic; for people moderately toxic. Like other rhododendrons it contains grayanotoxins: dangerous to grazing animals and pets.
- What grows well with Alpenrose (rusty-leaved alpenrose)?
- There is no well-documented companion pairing for Alpenrose (rusty-leaved alpenrose). Group it with plants that like the same sun (part sun to part shade) and water (moderate).
Sources and evidence
Evidence grade A (A: strong evidence).
- Plants of the World Online (taxonomy, native range), Royal Botanic Gardens, Kew
- Alpine Garden Society Encyclopaedia of Alpines and plant portraits, Alpine Garden Society, Pershore (UK)
Notes and assumptions
- A low, dense evergreen with leaves rusty-brown beneath and clusters of rosy-red tubular flowers in early summer, colouring whole hillsides of the Alps just above the tree line. Needs acid soil and snow cover or shelter in winter.
Reference values for planning, not horticultural, veterinary or medical advice. Varieties, soils and local climates differ: check with a local nursery or extension service.
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