Common Name: Flowering Rush
Scientific Name: Butomus umbellatus
Habitat: shorelines - mainly in water
Provincial Designation: Prohibited Noxious
Prohibited Noxious weeds are plant species designated in the Alberta Weed Control Act. Prohibited noxious weeds must be destroyed when found, meaning all growing parts need to be killed or the plant's reproductive mechanisms need to be rendered non-viable.
Flowering rush is native to Eurasia and was first found in Eastern Canada and since then it has spread across the country. It was introduced as an aquatic ornamental species that were planted in and around water features.
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 the soil where they can grow to new plants.
The purple to white flowers are arranged in a characteristic umbel (umbrella shape - a flower cluster in which stalks of nearly equal length spring from a common center and form a flat or curved surface) that sits at 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 leaves all grow directly from the ground and 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.
Learn more about this species:
See Fact Sheet - Alberta Invasive Species Council