Seaside Arrowgrass vs Mountain Alder - TreeTime.ca

Seaside Arrowgrass vs Mountain Alder

Alnus incana subsp. tenuifolia

Triglochin maritima

CUSTOM GROW

CUSTOM GROW

Mountain Alder
Seaside Arrowgrass

Mountain Alder is a native cold-hardy shrub or small tree often found along streams and in moist forested habitats. Its nitrogen-fixing ability enriches soils and supports surrounding vegetation, while its extensive root system helps stabilize streambanks and slopes. The fast growth rate allows it to establish quickly on disturbed sites, making it especially valuable in reclamation, restoration, and erosion control projects.

Often forming dense thickets, Mountain Alder enhances habitat quality in riparian and upland areas. It provides food and cover for various wildlife, including birds and small mammals. Recognized as an important species for soil and water conservation, it is well suited for riparian planting, naturalization, and ecological restoration.

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

Seaside Arrowgrass is a native perennial commonly found in wetlands, salt marshes, and moist meadows. It is especially suitable for difficult growing sites. Its dense root system helps stabilize soil, while also providing food, cover, and habitat for small animals within the wetland community.

Seaside Arrowgrass is suitable for shoreline stabilization, wetland restoration, and naturalization projects.

Mountain Alder Quick Facts

Seaside Arrowgrass Quick Facts

Zone: 1a
Zone: 1b
Height: 6 m (20 ft)
Height: 0.5 m (1.5 ft)
Spread: 3 m (10 ft)
Spread: 0.3 m (1.0 ft)
Light: partial shade, full sun
Light: full sun
Moisture: normal, wet
Moisture: wet
Growth rate: medium
Growth rate: medium
Life span: medium
Life span: short
Growth form: multi-stemmed, thicket-forming
Growth form: upright, clump-forming
Spreading: rhizomes - medium, seeds - low, layering - low
Spreading: rhizomes-low, seeds-low


Toxicity: can be toxic to humans and livestock
Bark: smooth, gray to brown
Flowers: very small, pinkish-white, hair like
Bloom time: spring to early summer
Hybrid: no
Hybrid: no
Catkins: yes
Catkins: no


Native to: AB, BC, SK, YT, NT
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, NU, PE
Other Names: river alder, speckled alder, thin-leaved alder, thinleaf alder, western river alder
Other Names: common arrowgrass, common bog arrowgrass, shore arrowgrass