Alnus rubra
red alder
A medium-sized tree, to around 19m, fast-growing with a graceful habit, producing a narrow pyramidal head with rather pendulous branches. Leaves large, lobed, dark green above, greyish beneath. Long male catkins to 15cm. Fruits barrel-shaped, to 1.5cm long
Synonyms
Alnus oregana
Size
Ultimate height
Higher than 12 metresTime to ultimate height
20–50 yearsUltimate spread
4–8 metresGrowing conditions
Moisture
Moist but well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Yellow | Green | ||
|---|---|---|---|---|
| Summer | Green | Brown | ||
| Autumn | Green | Brown | ||
| Winter |
Position
- Full sun
Aspect
West–facing or South–facing or East–facing
Exposure
Exposed or Sheltered Hardiness
H7Botanical details
- Family
- Betulaceae
- Native to GB / Ireland
- No
- Foliage
- Deciduous
- Habit
- Columnar upright
- Genus
Alnus are vigorous deciduous trees and large shrubs with rounded leaves and often conspicuous catkins in winter
- Name status
Correct
- Plant range
- Alaska to California
How to grow
Cultivation
This genus is noted for its ability to thrive in poor, wet conditions and is widely used in land reclamation
Propagation
Propagate by seed in a seedbed as soon as ripe. Root hardwood cuttings in winter and softwood cuttings in summer. Bud grafting can be performed in late summer
Suggested planting locations and garden types
- Architectural
- Wildlife gardens
- Low Maintenance
- Hedging and screens
Pruning
Requires minimal pruning
Pests
Generally pest-free
Diseases
May be susceptible to Phytophthora and honey fungus
Get involved
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