Common Alder (Alnus glutinosa)

Common Alder, known botanically as Alnus glutinosa, is a medium to large deciduous tree, native to the UK and much of Europe. Valued for its rapid growth, nitrogen-fixing ability, and adaptability to wet conditions, the Common Alder is a vital species in riparian habitats, often found along rivers, ponds, and wetlands. Its glossy green leaves, catkins, and distinctive woody cones provide year-round interest, making it a versatile choice for both ecological and ornamental planting.

Common Alder is a robust and low-maintenance tree that thrives in a variety of challenging conditions, particularly in wet soils where other species may struggle. It requires minimal care once established, though young trees benefit from watering during dry periods. Pruning is rarely necessary, but it can be carried out in late winter to maintain shape or remove dead or damaged branches. Alder's natural resilience makes it suitable for urban environments and polluted areas.

Common Alder is particularly well-suited for planting in wet or waterlogged soils, making it an excellent choice for riverbanks, ponds, and floodplains. It is often used in reforestation projects, wetland restoration, and as a pioneer species in challenging sites. The tree's nitrogen-fixing roots improve soil fertility, benefiting surrounding plants. Additionally, its timber is valued for its durability in water, commonly used in construction, fencing, and furniture. Its dense foliage also provides shelter and nesting sites for birds and other wildlife.

Characteristics:

Height: 15m – 25m
Spread: 6m – 10m
Growth Rate: Fast
Position: Full sun to partial shade
Soil: Thrives in moist to wet soils; tolerant of poor, waterlogged, and compacted soils
Leaves: Rounded, glossy green leaves with a slightly sticky texture, turning yellow in autumn
Flowers: Yellow-brown catkins (male) and smaller red catkins (female) appear in early spring
Cones: Small, woody cones develop in autumn, persisting on the tree through winter
Bark: Smooth, dark grey bark that becomes more fissured with age