Black Alder

Fearnóg
Latin name: Alnus glutinosa

Alder Tree
Courtesy of Coillte Teoranta

The black alder is a deciduous tree, and a member of the birch tree family. It usually grows to about 20-25 metres tall, and extremely quickly too - up to half a metre each year! How much do you grow each year?

The black alder thrives in very moist, marshy ground. If you live near a river or a lake, you’re likely to find an alder tree growing nearby. Lots of people use it when planting a hedge as its leaves provide great shelter from the wind.

The broad, rounded leaves of the alder begin to open out in April. The leaves of the alder are very healthy looking, with their deep, green colour and smooth, glossy texture. Like other deciduous trees, the leaves are eventually shed in the autumn.

Catkins are the name given to the flowers of the alder that blossom out in March. When the female catkins have been pollinated, a small cluster of four green, rounded cones will grow. They eventually change to a woody texture, and in the autumn they release little red-brown coloured seeds. These seeds are eaten by lots of different birds like siskens and redpoles.

Did you know?

Did you know that alder wood is traditionally used to produce smoked meats and fish?

Alder wood is also used for dying and wood turning as well as making making harps, clogs, and charcoal. It was once known as Irish Mahogany.

The Celts regarded the alder as a very special tree because when it is cut, the colour changes from white to red. The Celts believed that this tree held diving powers, especially when identifying diseases. It was considered a great offence to cut an alder down.