Hi, You didn't say if you lived in northern Minnesota zones
2&3 or southern zone
4. There are a lot of shady plants. Some flowering plants for zone
4 are Poker Primrose hieght 12-24 inches tall, Wood Poppy 18 inches tall. Some that are are hardy to zone
3 and would be hardy to zone
4 are the Astilbe's in Lavender, Pink,Red,White 14-18 inches tall,
Blue Columbine 24-36 inches tall and the red and white Bleeding Hearts. There are also so many textured plants that do well in your area. I myself thought I was doomed when the family tree grew bigger and bigger and my sunny garden became smaller and smaller, but I found some wonderful plants for the shade and I love them. Good luck with your shade garden, let me know how you make out.