Woolgrass vs Water Arum - TreeTime.ca

Woolgrass vs Water Arum

Calla palustris

Scirpus cyperinus

CUSTOM GROW

CUSTOM GROW

Water Arum
Woolgrass

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.

Woolgrass is a native perennial sedge that forms dense clumps in wetlands, ditches, and along shorelines. Its ability to thrive in saturated soils and shallow water, combined with its spreading growth habit, makes it especially valuable for waterside & riparian plantings, erosion control, ecological restoration, and naturalization projects.

The distinctive spikelets are covered in brown woolly bristles, which is where it gets the name Woolgrass. It produces seeds that are eaten by waterfowl and small mammals, while its dense stems offer cover and nesting habitat. It grows most actively in spring and fall, slowing or going dormant in the summer heat.

Water Arum Quick Facts

Woolgrass Quick Facts

Zone: 1b
Zone: 3a
Height: 0.2 m (0.8 ft)
Height: 1.5 m (5 ft)
Spread: 0.2 m (0.8 ft)
Spread: 0.9 m (3 ft)
Light: shade, partial shade
Light: partial shade, full sun
Moisture: wet
Moisture: wet
Growth rate: medium
Growth rate: fast
Life span: short
Life span: short
Growth form: colony-forming
Growth form: upright, colony-forming
Spreading: rhizomes - medium, seeds - low
Spreading: rhizomes - medium

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: no


Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, PE
Native to: MB, ON, QC, NS, NB, NL, PE
Other Names: bog arum, swamp lily, wild calla, wild dragon
Other Names: brown woolly sedge, common woolgrass, common woolly bulrush, cottongrass bulrush, marsh bulrush, wool grass