Alnus glutinosa (L.) Gaertn.
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Alnus glutinosa is a tree.
Alnus glutinosa was already described and the name validly published by Carl Linnaeus. It was Joseph Gaertner, however, who reclassified it into todays valid botanical systematics in 1790.
The trees are comparatively fast-growing and long-lived. They reach heights of 10 to 20 metres and have a broadly conical canopy The main growing season is in spring and summer. The plants reach a width of 8 to 15 metres.
Wood and Bark
The bark is thick or longitudinally fissured and grey.
Alnus glutinosa is deciduous. The green, simple leaves are alternate. They are ovate and petiolate with entire margins and pinnate venation. The foliage is porous.
Flowers and Fruits
Alnus glutinosa produces spikes of pendant, chocolate-coloured cruciform flowers from March to April. The plants are dioecious, pollination takes places by allogamy through the wind.
From summer to autumn the trees produce only few ornamental brown cones that are persistent on the plant.
The plants form shallow roots.
Alnus glutinosa is native to Europe and western Asia.
The trees prefer a sunny to half-shady situation on moist to wet soil. The substrate should be loamy, sandy-loamy, gritty-loamy, clay, sandy clay, loamy clay or peaty and comparatively poor with a pH between 4,4 and 7,2. The plants need a soil depth of at least 41 centimetres for good growth. They tolerate temperatures down to -40Â°C (USDA zone 3) and need a frost-free period of at least 19 weeks. The plants are suited for the shores areas of and in natural standing bodies of water, spring protection, bank protection in hardwoos areas along wide flowing waters and bank protection of narrow flowing waters.
Classification after Prof. Dr. Sieber
- open areas
Tolerance of special soil conditions
- low: soil salinity, anaerobic soil, calcareous soil
- medium: drought
- high: city climate, road salt
The recommended planting distance is 5 to 6 metres. Suited for windbreaks and soil protection and for noise and dust protection, as well as suited as avenue tree, slope plant, specimen plant, greenery along roads, bee pasture and as plant providing shelter for birds. From a commercial point of view the trees can be used to produce pulpwood. The plants have moderate potential for fuelwood production.
Maintenance and Propagation
The plants usually need very little maintenance.
- Plants can be cut back down to the trunk (coppicing) as necessary.
Propagate by sowing. The seeds require vernalization. Also by cuttings.
Pests and Diseases
- Walter Erhardt, Erich GÃ¶tz, Nils BÃ¶deker, Siegmund Seybold: Der groÃe Zander. Eugen Ulmer KG, Stuttgart 2008, ISBN 978-3-8001-5406-7. (Ger.)
- Christoper Brickell (Editor-in-chief): RHS A-Z Encyclopedia of Garden Plants. Third edition. Dorling Kindersley, London 2003, ISBN 0-7513-3738-2.