Water Arum vs Lewis Mock Orange - TreeTime.ca

Water Arum vs Lewis Mock Orange

Philadelphus lewisii

Calla palustris

COMING SOON

(new stock expected: fall of 2026)

CUSTOM GROW

Lewis Mock Orange
Water Arum

Lewis Mock Orange is a flowering ornamental shrub that produces an abundance of white, fragrant blooms. The flowers have a sweet scent similar to orange blossoms, with a hint of pineapple. They bloom for several weeks from late spring to early summer, attracting pollinators and other beneficial insects.

Native to North America, Lewis Mock Orange is found from the southernmost portions of Alberta and British Columbia, and south into the northwestern United States. It makes an attractive shrub and can be used in hedgerows, pollinator gardens, and naturalization projects. Blooms occur on the previous year’s wood, so it is recommended to prune after it has finished flowering.

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.

Lewis Mock Orange Quick Facts

Water Arum Quick Facts

Zone: 4a
Zone: 1b
Height: 3 m (10 ft)
Height: 0.2 m (0.8 ft)
Spread: 2.4 m (8 ft)
Spread: 0.2 m (0.8 ft)
Light: partial shade, full sun
Light: shade, partial shade
Moisture: dry, normal
Moisture: wet
Growth rate: medium
Growth rate: medium
Life span: medium
Life span: short
Growth form: upright to arching, multi-stemmed
Growth form: colony-forming
Spreading: suckering - medium, seeds - low
Spreading: rhizomes - medium, seeds - low


Toxicity: toxic if ingested
Flowers: fragrant, white
Flowers: white sheath around and yellow spike
Bloom time: mid spring to early summer
Bloom time: spring to summer
Berries: red, in clusters
Hybrid: no
Hybrid: no
Catkins: no
Catkins: no


Native to: AB, BC
Native to: AB, BC, SK, MB, ON, QC, NS, NB, NL, YT, NT, PE
Other Names: california mock orange, lewis mockorange, western mock orange, western syringa, wild mock orange
Other Names: bog arum, swamp lily, wild calla, wild dragon