Thinleaf Alder

Alnus incana subsp. tenuifolia

Cultivars: '(typically sold as species)'

Thinleaf alder is a native riparian tree or large shrub commonly found along streams and moist valleys in the Rocky Mountain region. It develops a multi-stem or single-trunk form with a rounded canopy and medium green leaves. In landscape settings, it is valued for naturalistic plantings, restoration projects, and areas near water features. Its fine texture and moderate size allow it to blend well into native or wildlife-friendly landscapes. The bark is smooth and gray, and the tree produces small cone-like structures that add subtle winter interest.

Plant Characteristics
Plant Color
Green
Flower Color
Yellow catkins
Bloom Time
Early Spring
Fall Color
Yellow
Height
15-20'
Width
10-12'
Water Use
High
Care Instructions

Thinleaf alder prefers full sun to partial sun and moist, well-drained soils. It has high water needs and performs best with consistent moisture. It is well suited for areas near streams, ponds, or irrigated landscapes. Pruning is minimal and typically limited to removing damaged or crossing branches. Winter protection is not usually necessary in the Rocky Mountain region. With proper moisture and placement, it serves as a useful native tree for naturalized landscapes.