As summer comes to an end in Minnesota, environmental officials and lake visitors are still focused on controlling aquatic invasive species. One success story is unfolding on Lake Melissa in Becker County, where a decade-long battle against an invasive plant called flowering rush is showing strong results.
The Pelican River Watershed District began treating flowering rush in 2013, when the plant was spreading rapidly across both Lake Melissa and nearby Detroit Lakes. At the time, hundreds of acres were affected. The invasive species poses a serious threat to lake ecosystems because it can quickly take over, crowding out native plants and disrupting the balance of the habitat.
Shanna Bach from the Pelican River Watershed District said the progress has been encouraging. “We’re definitely making a difference,” she explained.
This summer, the district is treating only 22 acres on Lake Melissa—compared to the hundreds of acres that needed treatment ten years ago. The major reduction in infested areas is being credited to consistent and carefully managed treatments over the years.
The main treatment method uses a chemical herbicide called diquat. While effective, diquat can be harmful if not applied correctly. It poses a risk to fish if misused and should never be swallowed. Because it is a weed killer, lake water treated with diquat should not be used for watering lawns or gardens, as it could damage plants. However, it is safe for swimming and fishing once applied properly.
Rick Michaelson, president of the Pelican River Watershed Board, emphasized the importance of using the herbicide correctly. “We don’t want people to irrigate their yards if they’re using lake water, because that could damage their lawns. But you can swim in it, you can fish in it—it doesn’t affect the fish in the lake,” he said.
Controlling flowering rush is not only about protecting Lake Melissa. The plant can easily spread to other lakes if pieces of it are carried away on boats or fishing equipment. Bach explained that many visitors come to the lake for a day of fishing, and if they pass through areas where the plant grows, small fragments can stick to their boats. If those boats are not cleaned before heading to another lake, the invasive species can spread across the state.
Because of this risk, local officials stress the importance of cleaning, draining, and drying boats and equipment before moving them between lakes. This is one of the simplest yet most effective ways to stop invasive plants from spreading.
The shoreline of Lake Melissa has become more popular in recent years, with more homes and cabins being built. This increased activity makes the fight against invasive species even more important. Healthy, clean lakes are vital for fishing, swimming, boating, and the local economy.
The methods developed by the Pelican River Watershed District for controlling flowering rush have proven so effective that they are now being used statewide. The project has also benefited from research support, including work from Concordia College professor Dr. Michelle Marko, who was involved in the early stages of the study back in 2013.
After more than a decade of effort, Lake Melissa’s situation is a strong example of how persistence and science-based strategies can protect Minnesota’s lakes. While the fight against invasive species is ongoing, the success here offers hope for other lakes dealing with similar challenges.
As Bach put it, “It’s been a long road, but we’re seeing results. If we can keep it up, we can protect these lakes for future generations.”
