Grey Alder, Speckled alder, Thinleaf alder, White Alder

Alnus incana

Physical Characteristics

Alnus incana is a deciduous Tree growing to 18 m (59ft) by 5 m (16ft) at a fast rate. See above for USDA hardiness. It is hardy to UK zone 2. It is in flower from February to March. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Wind. It can fix Nitrogen. Suitable for: medium (loamy) and heavy (clay) soils and can grow in heavy clay and nutritionally poor soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry moist or wet soil. The plant can tolerate maritime exposure.

Distribution

Europe. Introduced in Britain[17].

Habitats

Woodland Garden Canopy; Bog Garden;

Edible Uses

The inner bark is technically edible but of very poor quality. It contains high levels of bitter tannins that require extensive processing—boiling in multiple changes of water, drying, and grinding into flour. Even then, the bitterness persists, and the flour has little nutritional value. The bark is available year-round but should only be considered as a survival food, and even then, only if mixed with more nutritious ingredients. The flowers (catkins) are a better resource. Male catkins, which appear from late winter through early summer, can be boiled and eaten. They have a distinctive, somewhat bitter and resinous flavor, but are tolerable compared to other alder parts. The texture is dry, grainy, and fully chewable. Male catkins can also be harvested for their pollen, which can be sifted off and sprinkled back onto the cooked catkins; however, pollen may trigger allergies in sensitive individuals. Female catkins are small and woody, eventually maturing into cone-like structures that are not suitable for food. The sap and other tissues of alder contain tannins and are not suitable for consumption as food.

Medicinal Uses

None known

Known Hazards

None known