How hard can you cut back a hedge?

[Keitai]

This hedge hanging massively over pavement. Can I cut it back to edge or will it remain brown forever if I do? Looked for green beds in what was left after I cut it back. Found one

 

[jj4091]

I'm not an expert and don't know what type of shrub or hedge that is ( possibly privet )but my guess is that the side in the pic. is north facing or gets very little sunshine. If it were mine I would cut it back very hard,to about 4 foot high and definately off the pavement. Then thin the other side until it was a about 2' 6" deep. That should allow more sun to get through to the pavement side and thicken the hedge evenly when it regrows. I would guess it's pretty fast growing so once it gets to the dimensions you require trim both sides regularly and don't let it get out of control again.

 

[Alec_t]

According to Google's image search:-
"The plant in the image appears to be an Elaeagnus hedge, such as an Ebbing's silverberry (Elaeagnus × ebbingei) or a similar oleaster variety".
And according to ChatGPT:-
"Oleaster (Elaeagnus × ebbingei) generally responds very well to hard pruning and can regrow vigorously afterwards.
It tolerates being cut back quite severely, even into older wood
The best time for a hard renovation prune is late winter or early spring, before strong new growth begins.
If the hedge is very overgrown, you can reduce it substantially, but for a very severe cut it can be safer to do it over 2–3 years, rather than removing everything at once."

 

[Munroast]

not 100% sure, but you could probably cut that back to a 6" stump poking out of the ground - it would probably go back 5 or 6 years - don't let it get out of control as much the ext time