The City of Chestermere is pleased to collaborate with Alberta Agriculture & Forestry to better understand aquatic invasive species and the best methods to eradicate them. Ms. Nicole Kimmel will be in Chestermere throughout the summer conducting a research project on Flowering Rush. If you see any of these plants, do not remove or touch them as disturbing them can cause them to spread more easily. More information about aquatic invasive species in Chestermere is available at www.chestermere.ca/ais. 

Evaluating flowering rush control efforts in Alberta

By Nicole Kimmel, Weed Specialist with Alberta Agriculture & Forestry

               Due to human colonization and disturbance, invasive species have rapidly increased worldwide and are currently the second leading cause of biodiversity loss. Invasive species threaten the environment, the economy and human health as they establish in areas outside their natural range. Canada spends an estimated $30 billion annually on invasive species management, with $20 billion allocated to the forest sector, $7 billion to aquatic invasive species in the Great Lakes and $2.2 billion to the agricultural sector. However, terrestrial invasive species management do not face the same challenges as aquatic invasives. In aquatics having a lack of effective control methods and experience make detection and rapid response difficult in the province.

Introduced from Europe as an ornamental plant, flowering rush (Butomus umbellatus L.) has quickly secured a home in Alberta. Currently, it is found in 13 locations within Alberta. This species can grow completely or partially submerged along the shoreline where its triangular stem and sword-like leaves will surface. When in bloom, the distinct umbrella shaped clusters of pink and white flowers help in identification in dense stands within the water.

Flowering rush may pose a serious threat by reducing the water quality and availability for native vegetation and wildlife. Under the Alberta Weed Control Act and the Alberta Fisheries Act, flowering rush is listed as prohibited meaning it must be eradicated when found. Once established, this species is extremely difficult to control. Flowering rush can reproduce sexually by seed or vegetatively by fragmentation of rhizomes and small bulbs known as bulbils, complicating management efforts. However, spread in Alberta is primarily through bulbils and rhizomes dispersed by human, animal or boat. This species is largely concerning to the Western Irrigation District (WID) because it supplies irrigation water to over 400 farms and 96,000 acres of cropland, which may further disperse this invasive species as well as negatively impact associated stakeholders.

This project will contribute to our understanding of flowering rush control management. Little is known about flowering rush management in general and no proven methods for eradication in Alberta can be recommended or applied. The objective of this research is to assess the most effective control treatment for flowering rush in the hopes of eventual eradication and reclamation in affected areas. In Chestermere Lake, treatments for this project include hand removal (under 3 timings of removal), mechanical harvesting, removal & re-vegetation, benthic barriers (fabric & rubber) and diver-assisted suction harvesting. This project joins other efforts on flowering rush control in large scale in Alberta with goals to establish a procedure and effective control to be applied to similar locations.