Water Arum vs Nodding Onion - TreeTime.ca

Water Arum vs Nodding Onion

Allium cernuum

Calla palustris

NOT AVAILABLE THIS SEASON - MIGHT RETURN

CUSTOM GROW

Nodding Onion
Water Arum

Nodding Onion is a native perennial wildflower known for its nodding clusters of flowers that range in color from white to pink to purple. The lightly scented blooms provide pollen and nectar for pollinators, especially bees, which can collect while hanging upside down, a capability most other insects lack.

The narrow, grass-like leaves of the Nodding Onion can be used as a seasoning in cooked dishes, though bulbs and raw leaves should not be eaten in large quantities. All parts of the plant have an onion-like aroma when bruised, which helps deter deer and rabbits. They can self-seed readily, so removing spent blooms helps manage their spread. Tolerant of a range of soils, including alkaline, it is well-suited for a variety of plantings, including pollinator gardens and naturalization projects.

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.

Nodding Onion Quick Facts

Water Arum Quick Facts

Zone: 3a
Zone: 1b
Height: 0.3 m (1.0 ft)
Height: 0.2 m (0.8 ft)
Spread: 0.2 m (0.5 ft)
Spread: 0.2 m (0.8 ft)
Light: partial shade, full sun
Light: shade, partial shade
Moisture: dry, normal
Moisture: wet
Growth rate: fast
Growth rate: medium
Life span: short
Life span: short
Growth form: upright to spreading, clump-forming
Growth form: colony-forming
Spreading: seeds - high
Spreading: rhizomes - medium, seeds - low
Maintenance: medium

Toxicity: raw leaves and bulbs can be midly toxic

Toxicity: toxic if ingested
Foliage: smells of onion when crushed, edible
Flowers: white, pink, or purple nodding clusters
Flowers: white sheath around and yellow spike
Bloom time: late spring to summer
Bloom time: spring to summer
Berries: red, in clusters
Hybrid: no
Hybrid: no
Catkins: no
Catkins: no


Native to: AB, BC, SK, ON
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, PE
Other Names: ladys leek, nodding wild onion
Other Names: bog arum, swamp lily, wild calla, wild dragon