Are you struggling to find a tree that grows well on poorer soils? Look no further than Alnus crispa, also known as Mountain Alder! This large shrub or small tree is native to northeastern North America and Greenland, and features smooth grey bark even in old age. Its shiny green leaves with light green undersurfaces are ovoid, 3-8 cm long and 2-6 cm broad, and its flowers appear late in the spring, after the leaves emerge. Unlike other alders, it flowers before leafing out. The male catkins are pendulous, 4-8 cm long, while the female catkins are 1 cm long and 0.7 cm broad when mature in late autumn, in clusters of 3-10 on a branched stem. The seeds are small, light brown with a narrow encircling wing.
Alnus crispa is also known for its nitrogen-fixing nodules, making it a great option for afforestation on infertile soils. It enriches the soil with nitrogen while not growing large enough to compete with the intended timber crop. This tree can add up to 55 lbs of nitrogen per acre per year to the soil. Additionally, Alnus crispa is a light-demanding, fast-growing shrub that can grow well on poorer soils. Not only is Alnus crispa great for the environment, but it also has medicinal uses. In traditional Austrian medicine, its leaves have been used externally or internally as tea for treating infections and fever. So why wait? Enhance your soil while also experiencing the beauty and benefits of the Mountain Alder.