Good Morning, 

Thank you for contacting the U of M Extension Service. 

Please click on the following link from the U of M Extension Yard and Garden website:

https://extension.umn.edu/lawn-care/mushrooms-lawns

Although you may not have mushrooms growing, it discusses fairy circles. These have appeared during the rainy and wet weather we've been having. 

Here is a link to the MN Lawn Care Calendar: https://extension.umn.edu/planting-and-growing-guides/lawn-care-calendar

Since your property borders on water, here is information you might consider to enhance and stabilize your shoreline for wildlife and pollinators: 

https://extension.umn.edu/lakes-and-wetlands/shoreland-properties#building-and-landscape-planning-1904260

You might consider doing the yard survey under this website: 

https://extension.umn.edu/lawns-and-landscapes/flowers-pollinators

Good Luck!