Green Alder vs Water Arum - TreeTime.ca

Green Alder vs Water Arum

Calla palustris

Alnus alnobetula subsp. crispa

CUSTOM GROW

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Water Arum
Green Alder

Water Arum is a native perennial wetland plant known for its showy white oval sheaths (spathe) that surround a yellow-green, cylindrical flower spike (spadix). It has large, oblong, heart-shaped leaves on stems that rise above the water from shallow, spreading rhizomes. The blossoms are followed in late summer by tiny, pear-shaped fruits that ripen to bright red, adding ornamental interest to wet habitats.

Water Arum provides food for birds and small mammals that eat its berries, and its flowers attract pollinators. It can tolerate cold climates and forms colonies in shallow water and saturated soils. It is well-suited for ecological restoration, riparian planting, naturalisation, and habitat projects in wet and shaded environments.

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.

Water Arum Quick Facts

Green Alder Quick Facts

Zone: 1b
Zone: 1a
Height: 0.2 m (0.8 ft)
Height: 7 m (23 ft)
Spread: 0.2 m (0.8 ft)
Spread: 3 m (10 ft)
Light: shade, partial shade
Light: any
Moisture: wet
Moisture: any
Growth rate: medium
Growth rate: fast
Life span: short
Life span: short
Growth form: colony-forming
Spreading: rhizomes - medium, seeds - low
Suckering: high

Toxicity: toxic if ingested

Flowers: white sheath around and yellow spike
Bloom time: spring to summer
Berries: red, in clusters
Hybrid: no
Hybrid: no
Catkins: no
Catkins: yes


In row spacing: 0.9 m (3 ft)
Between row spacing: 5 m (16 ft)
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, PE
Native to: AB, SK, MB, ON, NS, NB, NL, YT
Other Names: bog arum, swamp lily, wild calla, wild dragon
Other Names: american green alder