Lagoon Foliage

Asked May 25, 2019, 9:29 AM EDT

Hello MSU friends.... (5 MSU diploma's at our house !!!) Attached are three photos of a new foliage which has surfaced in our lagoon by our home in Luna Pier, Michigan. Cannot remember this appearing in years past. We did spray for foliage eradication last year (duckweed, invasive weeds...) via a company in Brighton, Michigan - perhaps that spraying caused the new weed? Three questions - 1. Can you identify this weed. We think it is Potamogeton Crispus (Curly-leaf pondweed) 2. How do you eradicate this weed? Will it require a permit from MDEQ or another agency? 3. Can you help us in resolving this?.... our lagoons / canal are about 36 feet wide by 4000 feet long (5 lagoons running east/west and one north/south canal).

Monroe County Michigan

1 Response

Hello, fellow Spartans!

You are correct. This is curly-leaf pondweed (P. crispus), an invasive species.

Spraying with herbicides is the typical approach for removing this plant, and any spraying requires a permit from EGLE (formerly DEQ). If you hire a company, they will obtain the permit for you. You can learn about the process on the EGLE Aquatic Nuisance Control website: Hand removal (by hand or with a rake) in relatively small areas does not require a permit, but from what I see it is already growing quite thickly in your canal.

Spraying to kill unwanted plants does open up an opportunity for other plants to take their place. Curly-leaf pondweed has a competitive advantage because it starts growing earlier in the season than most other aquatic plants, giving it a head start. That is a general challenge in plant management - removing one species provides an opportunity for another.