This week we take a look at another invaluable native tree species ~ Alnus glutinosa (Alder). This deciduous species is a member of the same family as silver birch (Betulaceae) and can grow to 25 metres in height at quite a fast rate. Flowering in spring, with seed ripening in autumn, alder is a common sight in marsh and fen areas, alongside lakes and in wet areas of woods.
Cultivation & Care
Alder enjoys a sunny spot but will also tolerate light shade. It will grow in dry soils but does not tend to live for as long in such a situation. It does however favour heavy wet soils and can tolerate its roots being submerged in water up to 30 cm deep.
Compassionate Roots can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally and when in doubt about eating a plant you have not eaten before.
Alder provides many functions and uses to both humans and nature alike. Below are just some of those uses.
- Dye ~ This can be produced from the bark, shoots and catkins.
- Edible sap ~ This can be consumed as is or concentrated into a syrup. (Alnus rubra)
- Nitrogen fixer
- Coppice plant ~ Due to how rapidly it grows, alder is a great plant to coppice for wood for crafting tools, particularly tools which need to be tolerant of exposure to wet conditions.
- Erosion control ~ Especially good for erosion prevention on steep slopes.
- Edible catkins ~ Can be eaten raw or cooked. (Alnus rubra)
- Pioneer species ~ Great for revitalising former farmland or difficult sites as it grows rapidly, fixes nitrogen, adds plenty of leaf litter to help build the soil and will die back when larger trees establish in the area.
- Medicinal uses ~ The bark is used to achieve various results on the body including: alterative, astringent, cathartic, febrifuge and tonic.
I’ve listed some of the benefits alder provides for humans and habitat but what about actual wildlife?
- Shelter ~ Shrub formed species make great shelter for wildlife such as Alnus incana subsp. rugosa and Alnus serrulata.
- Nectar and pollen plant ~ A great source of food for our precious pollinators, particularly bees.
- Caterpillar food ~ The foliage provides food for many species of moth caterpillar.
- Bird food ~ The seeds are a great source of nutrition for redpoll, siskin and goldfinch species.
- Otter nesting ~ When growing near bodies of water, the roots provide a great nest site for otters.