Green Alder vs Black Locust - TreeTime.ca

Green Alder vs Black Locust

Alnus alnobetula subsp. crispa

Robinia pseudoacacia

Green Alder
Black Locust

Green Alder is a native, cold-hardy shrub found in boreal forests, along slopes, and in open upland habitats. It fixes nitrogen in the soil, improving fertility and helping other plants grow, while its roots help stabilize slopes and disturbed ground. Fast to establish on poor soils, it is widely used in reclamation, restoration, and erosion control projects.

With its smooth grey bark and shiny green leaves, Green Alder often forms dense thickets that provide cover for birds and small mammals. Its seeds, buds, and catkins also supply food for wildlife. Green Alder is well suited for naturalization and ecological restoration.

Note: We use Green Alder for Alnus alnobetula subsp. crispa. This species is also known by many other common names, including Mountain Alder, Sitka Alder, and others. Please confirm the scientific name to ensure you are ordering the correct plant.

Black Locust is an attractive tree. Its distinctive leaves are made of about a dozen bright green leaflets. It also notable for its fragrant white flowers, which smell of citrus.

Black Locust can grow in many situations, but prefers dry areas with lots of sun. It is robust and is an excellent choice for establishing shade in dry, open areas.

Important note: Much of the Black Locust is toxic to humans and livestock, including seeds, bark, and leaves.

Green Alder Quick Facts

Black Locust Quick Facts

Lowest Price: $3.49 - SAVE UP TO 42%
Lowest Price: $1.99 - SAVE UP TO 60%
Zone: 1a
Zone: 3a
Height: 7 m (23 ft)
Height: 12 m (40 ft)
Spread: 3 m (10 ft)
Spread: 8 m (25 ft)
Light: any
Light: full sun
Moisture: any
Moisture: dry, normal
Growth rate: fast
Growth rate: fast
Life span: short
Life span: long
Suckering: high
Suckering: high


Bark: dark reddish brown to balck with furrows
Flowers: Creamy white flowers in a pyramidal shape bloom in may-june
Seeds: dark brown peapod-like pods
Hybrid: no
Hybrid: no
Catkins: yes
Catkins: no

In row spacing: 0.9 m (3 ft)

Between row spacing: 5 m (16 ft)
Native to: AB, SK, MB, ON, NS, NB, NL, YT
Other Names: american green alder
Other Names: false acacia, yellow locust