Alnus
Deciduous Tree

USDA Zones: 3 - 7
Light: sun - partial shade
Height:  20 to 50 feet
Width:  15 feet
Flower Colors: purple-brown
Bloom Time: early spring
Special Features:
Easy to Grow
Fall Color
Fast Growing
Tolerates Wet Soil
Winter Interest

Alders are mostly large shade trees adapted to wet soil. They grow rapidly, with larger species reaching up to 40 feet within 20 years. Alders may be multi-trunked or have a single trunk, and have dark glossy, green leaves. They are best used along waterways in wild areas.

Notable Varieties
Common alder (A. glutinosa) reaches 60 feet tall and 40 feet wide. Improved cultivars include cut-leaved 'Imperialis' and 'Laciniata'. Good for wet sites.
White alder (A. incana) is good for wet sites as far north as zone 2. 'Aurea' has yellow leaves and 'Laciniata' has cut leaves.
Speckled alder (A. rugosa) is a shrub, to 15 feet.

Care
Prune in winter or early spring.

Planting
Plant balled-and-burlapped or container-grown plants in full sun or partial shade. Alders prefer moist or wet soil but perform well in dry soils and tolerate acid or slightly alkaline soils.