The way you manage hedgerows on your land makes a huge difference to their viability. A thriving, living landscape is beneficial to you in many respects, and to all who rely upon it. Food and shelter for wildlife and livestock are just part of the story.
A healthy hedge line also has a healthy root system that takes up surface water; to do this, it needs to regenerate naturally in spring from growth that has lain dormant from the autumn. When all this growth is sheared off, long shoots spring upwards in a desperate effort to regain height causing valuable energy to be needlessly lost, preventing foliage from restoring in time for nesting birds to find sites in early spring and preventing formation of berries and nuts.
Hedge plants subjected to annual cutting to the same height cannot provide any of the primary resources Nature designed them to perform. That they were originally planted by people is a positive piece of history, not a warranty against responsibility. However many generations farmed the land before you, the baton is in your hands now.
Please - leave the body of the hedge to flower and fruit next year if you decide to cut, and raise cutting height above 'knuckles' that have formed, lightly trimming new growth. No need to take out the underbrush - it doesn't get in anyone's way and helps birds, pollinators and hibernators survive through the winter. Ancient pleachers providing critical shelter and nest sites need to stay covered at all times, all year round.
Here is a local hedge trimmed back in summer for road safety reasons on a narrow country lane. (Most are cut within the September-March time frame.) There is foliage on these bushes, which will flower and fruit next year. Incremental cutting - leaving a few inches of growth on a hedge each time - preserves environmental integrity.
Ease back the blades, away from the core of the hedge - an easy implementation even if you still want to cut annually... but you don't have to cut annually! Rotational or incremental cutting is widely advised.
You can save diesel, aid carbon capture and prevent irreversible damage to the ecosystem by doing things differently this year.
Take a new approach and see what happens! You can have a living border that looks like a real hedge and functions as real hedges should! Let's put an end to this and promote genuine guardianship of the countryside.