Common Black Alder Trees
Alnus glutinosa is a native tree that loves growing in wet, boggy soil. Young plants are slender and have a narrow canopy; mature old trees can spread quite a bit. Alnus glutinosa has mid-green leaves, yellow catkins in spring and seed-bearing cones in the autumn, which are food for small birds. The catkins are wind-pollinated, but they still provide a source of protein-rich pollen for bees early in the year, when there isn't much else available. Note on Alder roots: Alder has invasive roots that can break old water pipes and damage the foundations of old buildings or walls. 15 metres away from vulnerable structures is a safe distance to plant Alder. New build, concrete foundations are not at risk. Common Alder trees can reach a height of about 25 metres.
How Standard Trees are Measured: All our standards, are graded by their girth in centimetres 1 metre above ground level (basically, their trunk's waist measurement). They aren't measured by their height, which will vary. So, a 6/8 standard has a trunk with a circumference of 6-8 centimetres and an 8/10 standard has a trunk 8-10 centimetres around. This measurement makes no difference to the tree's final height. Standard trees are 2.5 - 4.5 metres tall (on average) when they arrive; they are the most mature trees that you can buy from us.
History & uses of Alnus glutinosa: Alnus glutinosa is a classic pioneer tree that is often used in reclaiming sites with especially poor soils, due to the bacteria living in nodules in its roots. These bacteria fix nitrogen from the air into the soil, improving it for other plants.