Grey alder

Alnus incana | Rating: 0 votes | Print / Pdf

Alder is all you need if you want a fast growing tree for a wet site.

Alnus incana or grey alder was introduced to Europe in the 1770's. It will grow up to 20m high in a pyramid shape. It has grooved pointed oval leaves that are not glossy. They are a green grey colour. The bark is smooth, grey in colour. It has chunky looking catkins that are about 1cm wide and 1.5cm long, and a pinky yellow colour. A fast growing tree that will thrive in even poor soil as long as it gets plenty of sunlight. It likes a moist soil but will grow fine in dry soil too. It has good resistance to pollution so works well in a city setting.

Rate it:
Known dangers?
  • no
Height [m]
  • 20
Spread [m]
  • 10
Dominant flower colour
  • Yellow
Flower Fragrance
  • No, neutral please
Flowering seasons
  • Late winter
  • Early spring
Foliage in spring
  • Green
Foliage in summer
  • Green
Propagation methods
  • seed
  • budding
  • Hardwood cuttings
Growth habit
  • Conical
  • Clump-forming
  • Erect
  • Acidic
  • Neutral
  • Alkaline
Hardiness zone
  • Z2-6
Heat zone
  • H6-1
Winter temperatures [°C]
  • -46 - -18
Heat days
  • 0 - 60
  • well-drained
  • well-drained but frequently watered
Soil type
  • Clay
  • chalky
  • loams
Sun requirements
  • Full sun
  • Partial shade
  • Exposed
  • Sheltered
Standard category
  • Trees & shrubs
  • Trees
Grown for
  • Ornamental Foliage
Creative category
  • For Beginners
  • Bonsai
  • Pond plants
Garden type
  • Park
  • Pond
Garden spaces
  • Windbreak
Gardening expertise
  • beginner
Time to reach full size
  • 30 years or longer
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