Flowering Rush (Butomus umbellatus)

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Flowering rush is an exotic plant that has been introduced into several Alberta wetlands. It is an aquatic plant that can grow as an emergent plant along shorelines and as a submersed plant in lakes and rivers.

This exotic was likely brought to North America from Europe as a garden plant. While single flowering rush plants are not a "problem," this exotic can form dense stands which may interfere with recreational lake use. Flowering rush may also crowd out native plants and in turn harm fish and wildlife.

Nicole Kimmel, ARD
Key Identifiers
  • Easiest to identify when flowering. Flowers grow in umbrella shaped clusters and each individual flower has 3 whitish pink petals and 3 similar but smaller sepals. Plants only produce flowers in very shallow water or on dry sites.
  • Green stems are triangular in cross section.
  • Along shore, erect leaves and grows to about 3 feet in height. The leaf tips may be spirally twisted. Under water, the leaves are limp.
  • An extensive root system that can break into new plants if disturbed.
Location in Canada
Current distribution spans southern Canada from Nova Scotia to British Columbia. Alberta has had many confirmed sightings in 2011, in water course ways from southern Alberta to central Alberta.

Invasive Plant Atlas of the United States - Flowering Rush
Global Invasive Species Database - Flowering Rush
King County, Washington, Noxious Weeds - Flowering Rush

Similar species
Bur-reeds (Sparganium spp.)- leaves of flowering rush resemble bur-reed although the female flower parts resemble small, spiked balls.

Cattail (Typha latifolia) - leaves are flat not triangular

Rushes (Juncus spp.)- grass-like leaves, often egg-shaped in cross section and flowers considered non-showy.

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For more information about the content of this document, contact Chris Neeser.
This document is maintained by Shelley Barkley.
This information published to the web on April 10, 2012.
Last Reviewed/Revised on August 21, 2018.