© Denver Botanic Gardens

thinleaf alder
Alnus incana ssp. tenuifolia

Fort Collins

Synonyms: Alnus tenuifolia
Dimensions: Height: 15.0 ft. to 40.0 ft.
Spread: 15.0 ft. to 20.0 ft.
Growth Form: Shrub, Tree
Program Association: Nature in the City
Wildlife Uses: Amphibians/Reptiles, Fish, Large Mammals, Medium-Sized Mammals, Pollinators/ Invertebrates, Riparian Birds, Shrubland Birds, Wetland Birds, Woodland Birds
Sun Requirements: Full Sun, Part Sun
Water Requirements: Moderate, High
Plant Community: Foothills, Mountains, Plains
Season of Bloom: April, May, June, July
Flower Color: Brown Shades, Red Shades
Leaf Color: Green Shades
Aggressiveness: Not aggressive
Design Considerations: Winter Interest
Other Considerations: Lifespan, No City Data
Duration: Perennial
Natural Landscape Position: Fort Collins Model
3, 4, 5
Soil Type: Clay, Rocky, Sandy
Pests/Disease Prone: No
Hazards/Toxic: No City Data.

Notes

A small multi stem native alder that is best adapted to moist sites. Nice smooth grey bark and dark green foliage. Can handle some shade and does well against buildings. Tends to be short lived.

This is an important larval food host for many of our native invertebrates.

Flora of North America recognizes two subspecies of A. incana, both native to the United States. Subspecies rugosa is native to the northeastern U.S. and Canada and subspecies tenuifolia is native to the western U.S. including the Fort Collins area.