Constant overgrowth from private backyard onto public walkway

These private bushes/trees have been spilling over this wall for years, and keeps halving the walking space and forcing people into the streets when it gets really bad.

Pruning shouldn't really be necessary on the councils behalf in the first place, since it's private, but even when it gets pruned it just grows back to being a problem within 2 months. It seems like a waste of time and money to keep cutting the branches ever so slightly when it just grows back constantly, would be better to just trim the tree so the branches don't spill over the wall.