DETROIT LAKES — A watershed district in Detroit Lakes has been successful at preventing a non-native species from taking over four Becker County lakes.

The Pelican River Watershed District began tackling the invasion of flowering rush six years ago by doing basic scientific research on how the plant grows and thrives, according to a press release. The district spent about $25,000 a year on research.

“The problem with flowering rush is it grows a lot denser than our native hardstem bulrush, and then it has a tendency to change the substrate from a hard sandy gravel bottom to a mucky bottom,” said Brent Alcott, assistant administrator at the watershed.

John Madsen, who worked for the district when it started battling the invasive species, found that applying herbicide underwater was most effective.

“The main challenge was figuring out what is the key point in the life cycle of the flowering rush that is critical to be able to get long term control,” Madsen said.

Alcott said researchers have found success when they dig up the plant rhizomes after multiple herbicide treatments. It takes about three years to see a significant reduction in flowering rush, and requires about $50,000 of annual herbicide applications each year to control the invasive plant.

The treatment can be replicated anywhere, and others are starting to use it, Alcott said.

“The use of the protocols that have been developed for our treatment here are now being used in Wisconsin, they’re looking at bring them out to Idaho, down in the Twin Cities area they’ve been using them with pretty good success,” Alcott said.