Alnus incana
grey alder
A conical tree, to 20m, with dark-green leaves to 10cm long, grey-white and hairy beneath. Yellow-brown male catkins in pendent clusters of 3 or 4 are produced in late winter or early spring, before the leaves. Ovoid fruit is produced in summer
Other common names
American black aldercommon black alder
see moregray alder
hoary-leaved alder
speckled alder
_9374.JPG)
Size
Ultimate height
Higher than 12 metresTime to ultimate height
20–50 yearsUltimate spread
Wider than 8 metresGrowing conditions
Moisture
Moist but well–drained, Poorly–drained, Well–drainedpH
Acid, Alkaline, NeutralColour & scent
| Stem | Flower | Foliage | Fruit | |
| Spring | Brown Yellow | Green | ||
|---|---|---|---|---|
| Summer | Green | Brown | ||
| Autumn | Green | |||
| Winter | Brown Yellow |
Position
- Full sun
Aspect
North–facing or West–facing or East–facing or South–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
- Europe, Caucasus
How to grow
Cultivation
Grow in moderately fertile, moist but well-drained soil in full sun or part shade. Noted for its ability to thrive in poor, wet conditions but is also tolerant of dry soils
Propagation
Propagate by seed or hardwood cuttings
Suggested planting locations and garden types
- Coastal
- Cottage and informal garden
- Wildlife gardens
Pruning
Pruning group 1 between leaf fall and midwinter
Pests
May be susceptible to alder sucker, alder leaf beetle and leaf-mining sawflies
Diseases
May be susceptible to Phytophthora and honey fungus
Get involved
The Royal Horticultural Society is the UK’s leading gardening charity. We aim to enrich everyone’s life through plants, and make the UK a greener and more beautiful place.