Alder
Alnus glutinosa
Fast growing oval shaped tree maturing to 50′ X 40′. Tree prefers plenty of moisture but will tolerate dry, compacted urban soils as well. Has moderate tolerance of salt and will grow in full sun or partial shade. Very attractive branching, leaf shape and nut-like fruit that hangs on through the winter. Does not attract wildlife and is not messy. Very good choice for the Front Range and transplants easily.
Common Problems
Environmental
No significant issues. Alders will tend to grow multiple trunks and can be left to do so for screening or ornamental purposes. They can also be pruned to a single leader.
Diseases
None of significance. However, in Europe a disease similar to the potato blight that has caused significant death among the Alders.
Pests
Aphids and Leaf Miners are sometimes found in low pressure populations but are typically not an issue.
Cultivars
Several available.‘Aurea’, golden yellow leaves; ‘Fastigiata’ — narrow, upright form; ‘Laciniata’ leaves not as deeply lobed, vigorous growth; ‘Pyramidalis’,upright or columnar form to 50 feet tall, 25 feet wide.
History and Use
The earliest fossils date back to the Miocene about 18 million years ago. It has been traditionally grown for timber and firewood. It is used extensively for soil stabilization along river banks and for soil reclamation projects after such disturbances as mining or logging. They are a nitrogen fixing species meaning they make the soil significantly more hospitable to other tree species wherever they grow.
Not native to North America. The Alder establishes well, especially along waterways and other disturbed wet sites where it will propagate easily and form pure stands or thickets. It can be harvested for excellent furniture and cabinet grade lumber (Alnus rubra reaching 120 feet in height). Very attractive, clean and smooth, grain which lends itself to a very stable final product.
Alders tends to pull minerals from the soil and store them in the cells of their woody architecture. The bark is known to be used for treating burns and infections because of its chemical make up.
