Never been to Minnesota but here in a 4 County radius it's Jack central. Millions planted for a rare bird. Kirtland's Warbler.
Look for ones growing in ditches where they've been mowed. Or along trails where they've been ran over.
If you can find them growing next to wet areas they will have more compact root balls. They're into dry sandy areas.
You won't find decent ones inside a forest. Look on the edges of woodlines.