We just brought a house in Duluth. It is a fixer upper with a drainage issue. I am adding dry creeks to deal with that issue. What I can't figure out is if Duluth is the same zone as the Twin CIties. What zone is it. Do you have suggestions for plantings around a dry creek bed?
Check this web page with map of Duluth. Depends on where you live as the lake moderates things for plant hardiness http://www.plantmaps.com/hardiness-zones-for-duluth-minnesota
Generally NE Minnesota is on the cold end of zone 4, though right next to lake it is a bit warmer. There are some spots far inland in NE MN that reach down into zone 3. See also http://www.planthardiness.ars.usda.gov/