Green Alder
Alnus viridis subsp. crispa
Forms dense thickets in cold regions; important nitrogen-fixing pioneer shrub.
Field reference
Family
Betulaceae
Growth rate
Fast
Mature size
3–10 ft tall (rarely up to 15 ft), spreading thickets
Hardiness zone
2-6
Soil preference
Cold, wet, acidic soils; tundra edges, boreal slopes
Sun
Full Sun to Partial Shade
Pruning window
Late winter (generally not pruned; managed as shrub)
Wood properties
Very small-diameter stems; not used for timber; important for soil stabilization
Native range
Northern North America (Canada, Alaska, northern U.S.)
Green weight
40 lb/ft³
Pests & diseases to watch
Common questions
Is green alder a tree or shrub?
It is typically a multi-stemmed shrub rather than a true tree.
Where does Alnus viridis crispa grow?
It grows in boreal forests, tundra edges, and cold upland regions.
Does green alder fix nitrogen?
Yes. It improves soil fertility through nitrogen-fixing root nodules.
How tall does green alder get?
Most plants remain under 10 feet tall, forming dense thickets.
Is green alder good for erosion control?
Yes. It is widely used in cold-region stabilization projects.
Related species in Betulaceae
Tree Nerd Academy
Ready to sit the ISA Certified Arborist exam?
Video curriculum, flashcards, and exam-sim built by working arborists.