Q.Looking For A Thorn Bush.
My neighbor as a kid had a very fast growing hedge of thorn bushes. They quickly shot up to at least 6 or 7 feet tall. Pretty sure they had small white flowers on them as well. These were grown in the Detroit metropolitan area. I believe is zone 6?

Certified GKH Gardening Expert
From just the description, it can be very hard to know what the plant was, unfortunately.
There are a few things that it could have been. Flowering Quince, Roses, and Blackberries can all have white flowers.