No, it's not a Dogwood. Crataegus species i.e. a Hawthorn.

Flora, I trust you so know that you must be right. When I saw it at first it just said Dogwood to me. But the flowers do look like Hawthorn, but there don't seem to be thorns. I'll have to go back and look for them. It's only 100' from my property line. I'll collect seed this fall. Want some?

I don't know Crataegus very well other than to spot the genus but there are many and some have no thorns. It isn't a universal feature. C punctata might be a match for yours. It occurs in Mn.

Also remember that with but one exception, Dogwood (Cornus) has opposite leaves.