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Flowering Rush

Flowering rush
Photo Credit: Daniel Laubhann

Common Name: Flowering Rush

Scientific Name: Butomus umbellatus

Habitat: shorelines - mainly in water

Provincial Designation: Prohibited Noxious

Prohibited Noxious weeds are plant species that are designated as "prohibited noxious" in theAlberta weed regulation. Prohibited noxious weeds must be destroyed, meaning all growing parts need to be killed or the plant's reproductive mechanisms need to be rendered non-viable.

Origin

Flowering rush is native to Eurasia and was first found in 1897 in eastern Canada and since then it has spread across the country. It was introduced as an aquatic ornamental species that was planted in and around water features.

Legislated Because

This plant competes with native aquatic vegetation and reduces the habitat available for other wildlife. It is very hard to control and spreads quickly because it reproduces by seeds and by small root pieces that easily break off (bulbils). These bulbils float in the water until they get washed onto soil where they can grow to new plants.

Description

The purple to white flowers are arranged in a characteristic umbel that sits the end of a long leafless, round flowering stalk. Each flower is 2-2.5 cm in diameter and gives off a bitter almond scent.

The basal leaves are long and linear and have a characteristic triangular cross-section.

Flowering rush is an aquatic perennial species that can grow up to 90 cm tall and is often found along lakeshores and canals.