During the early Spring I purchased two cotoneasters from the discount rack at Lowe's. I took one of them and repotted it and slip potted the other one into a larger container. You can see these photos and notice that the cotoneaster on the right has significantly more foliage than the root pruned cotoneaster on the left.
This is how deciduous trees respond when root pruned. They will not put out more foliage than they can support with the root system and stored up energy from the previous Fall.