Alnus glutinosa

Betulaceae

Black Alder

Deciduous tree that can vary in height from 10-20m. Dark green leaves are obovate to round to 9cm and unspectacular in autumn. Bark is dark brown and deeply furrowed. Flowers are separate male and female catkins. Fruit are black, containing winged achenes. Syn. Alnus rotundifolia.

Uses

Suitable for waterlogged sites in cold climates. Regarded as a serious environmental weed in some regions (e.g. cooler areas of Australia). Don't plant within 4 metres of drainage systems.

Culture

Thrives in cool to cold climates in poorly-drained soil. Vulnerable to drought.

Propagation

Seed or hardwood cuttings.

Cultivars

'Aurea': Yellowish leaf variety.

A.g. var. barbata: Woolly, finely toothed leaves.

A.g. subsp. betuloides: similar leaves and form to the birch tree.

'Imperialis': Medium tree with a conical outline.

'Lanciniata': Deeply cut dark green leaves.

'Maculata': White dotted leaves.

'Pyramidalis': Narrower than the species.

'Razzmatazz': A rare form with yellow/green leaf margins in spring.

Plant Health

Propagate by stems or cuttings.

More info

Video: ‘Identifying Trees and Shrubs’ produced by Australian Correspondence Schools is available through http://www.acsgarden.com/shop/ Landscape Design and Home Garden Expert courses are available through Australian Correspondence Schools, see www.acs.edu.au/hort

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