Three years, and the dates are fixed
Michigan property taxes that go unpaid are returned as delinquent to the county treasurer, the parcel is forfeited the following March, and it is foreclosed the March after that. Once the foreclosure judgment enters and the redemption deadline passes, title vests absolutely in the foreclosing governmental unit and there is no post-sale redemption. It is a short, rigid calendar with hard dates rather than a slow drift, and the difference between acting in year two and year three is the difference between selling the land and not owning it.