Do consider adding at least a few native plants of Minnesota and the greater Midwest to your garden. Well-adapted to your climate,
they will likely be vigorous, beautiful, and easy to care for. They will also be a benefit to wildlife and your garden's ecology.
There are too many possibilities to make a list without first knowing more about your garden conditions and desires,
but do consider Milkweeds (Asclepias spp) and native daisies (Asteraceae) as they are often particularly deserving candidates.
I leave the flowers on my Lamb's Ears (Stachys byzantina), a spreading herb, in the Mint Family (Lamiaceae), native to Anatolia, the Caucasus, and Iran. The white woolly verticillasters make an interesting vertical element, and the purple flowers nestled in each hairy calyx, lend a touch of color and more food for the bees.