Plant Data Sheet

Click on this Photograph of Alnus incana to enlarge it and download  a high-resolution JPEG file

Species (common name, Latin name)

Mountain Alder, Alnus Incana



From central Alaska and the Yukon Territory, southeast to western Saskatchewan and British Columbia, and south to New Mexico and California.


Climate, elevation

Near sea level to 3000 m.


Habitat preferences

typically found near streams, rivers, or springs on moist mountain slopes on poorly developed soils of cobbles, gravels, or sands which remain moist year round due to high water tables


Plant strategy type/successional stage (stress-tolerator, competitor, weedy/colonizer, seral, late successional)

Thinleaf alder is an early successional plant. It is a nitrogen fixer and has a high flood tolerance and thus improves soil fertility and stabilizes streambanks.


Associated species

Black cottonwood, Maple, and Willow


May be collected as: (seed, layered, divisions, etc.)

Seed - best sown in a cold frame as soon as it is ripe and only just covered.

Cuttings of mature wood can be taken as soon as the leaves fall in autumn, outdoors in sandy soil.


Seed germination (needs dormancy breaking?)

Requires cold stratification


Seed life (can be stored, short shelf-life, long shelf-life)

Seeds have a short shelf-life.


Propagation recommendations (plant seeds, vegetative parts, cuttings, etc.) Spring sown seed should germinate successfully so long as it is not covered. The seed should germinate in the spring as the weather warms up. When large enough to handle, prick the seedlings out into individual pots. The seedlings can either be planted out into their permanent positions in the autumn/winter, or they can be allowed to grow on in the seed bed for a further season before planting them


Soil or medium requirements (inoculum necessary?)

Poorly developed soils of cobbles, gravels, or sands which remain moist year round


Installation form (form, potential for successful outcomes, cost)

May be planted as seed, container, or bare root.


Recommended planting density

300-1200 per acre.


Care requirements after installed (water weekly, water once etc.)

Water daily for the first year.


Normal rate of growth or spread; lifespan

Rapid growth, thicket forming with short lifespan.


Sources cited


Propagation of Pacific Northwest Native Plants by Rose, Robin.; Chachulski, Caryn E. C.; Haase, Diane L.,  Corvallis Oregon State University Press, 1998.,

Plants Database,


Data compiled by (student name and date)


Doug Schmitt 6-8-03