Black alder is a medium-sized, fast-growing, deciduous tree native to Europe, western Asia, and northern Africa, but has naturalized in other regions including the northeastern and central United States. It bears handsome, glossy, dark-green leaves from spring to fall, and its catkins provide mild interest in winter and early spring.
Requiring sun but thriving in most soils, it excels as a shade or screening tree in sites that are too damp or barren for other trees. It may be invasive in some situations. (Learn2Grow.com)
Genus - Alnus
Species - Glutinosa
Common name - Black Alder
Pre-Treatment - Required
Hardiness zones - 2 - 6
Height - 60'-80' / 18 - 24 m
Spread - 30'-35' / 9 - 11 m
Plant type - Medium Tree
Vegetation type - Deciduous
Exposure - Full Sun
Growth rate - Fast
Soil PH - Acidic, Neutral
Soil type - Clay, Loam, Sand
Water requirements - Average or High Water
Landscape uses - Bog Garden, Screening / Wind Break, Shade Trees
Bloom season - Early Spring, Winter, Late Winter
Leaf / Flower color - Green / Catkins
Seeds of alder requires 30-60 days cold moist stratification for best germination.
Stratification/ cold treatment: mix together equal amounts of sand and peat in a small container and moisten it with a little water. Mix the seeds in the medium and place it in the fridge at +2C (40F).
Keep the medium moist throughout the stratification period.
After stratification sow on surface, keep moist at room temperature in the light place.