About

Alnus inokumae is a rapidly growing deciduous tree that can reach heights of up to 30 meters. Its leaves measure approximately 8 centimeters in length and exhibit an oval form, featuring a green upper surface and a downy cream underside before they drop in autumn. In late winter, the tree produces male catkins, which cluster together and measure around 8 centimeters. The female cones, which are woody, remain attached to the branches throughout the winter months.

About the genus

Alnus comprises robust deciduous trees and sizable shrubs characterized by their rounded foliage and, during winter, noticeable catkins.

Growing conditions

Sunlight
Full sun
Soil type
Clay, Loam
Soil pH
Acid, Alkaline, Neutral
Soil moisture
Poorly-drained
Aspect
East-facing, North-facing, South-facing, West-facing
Exposure
Exposed, Sheltered
UK hardiness
H7

Plant details

Plant type
Trees
Habit
Columnar upright, Spreading branched
Foliage
Deciduous
Height
Higher than 12 metres
Spread
wider than 8 metres
Time to full height
20-50 years
Suggested uses
Architectural

Care notes

Cultivation
It is a nitrogen-fixer so can grow on poor soil. Suited to river banks on permanently damp soil in good light. For more information see tree cultivation.
Pruning
Pruning group 1
Propagation
Propagate by hardwood cuttings or seed. For more advice see our information on how to propagate from seed (tree/shrub
Pest resistance
May be susceptible to alder leaf beetle, alder sucker and leaf-mining sawflies
Disease resistance
May be susceptible to phytophthora root rot and honey fungus