There are in fact strict timescales for carrying out this work, so that nesting birds are not disturbed and annual growth and blossom is not harmed.
Soil conditions also dictate - hedges adjoining heavy clay soils are trimmed in the autumn before the ground becomes wet and vehicles might get stuck or take soil from the fields onto roads.
Lighter soils allow access through the winter, especially when there is a hard frost. Farmers are also encouraged to trim hedges every two years in order to enhance the habitat. So much of this work is done mechanically nowadays. Despite the cost of machinery, it is quicker and, due to the skill of the operator, leaves a tidy and neat job when done. Some landowners also like to shape their hedges to mark out their estate, or to help the hedge grow and stay healthy.
The traditional method of hedge laying is a rare skill but still much admired. Sadly, it is almost a hobby now, only seen in competition as the economic cost of maintaining hedges this way is not justified. There are grants available to help the cost, or even volunteers who will offer their services without charge though neither options will fully overcome this cost factor. But the great advantage of hedge laying is that it keeps a hedge healthy and stockproof. There is no need for barbed wire because the bottom of the hedge has grown firm and strong. It also becomes 'gappy' and 'woody' with hollow areas in its heart - perfect for a mischievous calf or lamb to explore and escape, but not so helpful for efficient and safe stock management!
The laid hedge as it grows ( it becomes a six or seven year rotational task) makes an effective windbreak, and also a warm habitat for birds and wildlife. Soil erosion is prevented as the effects of wind and surface water are dissipated by the shield provided by the hedge. And not least, the landscape is enhanced, preserving the very nature of the English countryside by dividing it into field units rather than creating extensive tracts of arable land without a feature to be seen.
Some areas of the country have the natural feature of stone walls; they too require great skill to build and maintain and provide shelter and security for livestock. But in the south of England, with its fertile low ground, the splendour of hedges is to be admired and not taken for granted.
Coppicing is a woodland craft, rather than for hedgerows. Hazel and ash are the preferred varieties - willow, in wetland areas. Coppicing is also rotational. As well as being good woodland management, it provides the materials for making hurdles, thatching spars, tools, baskets and for many other purposes - plus it keeps a healthy and attractive woodland habitat for wildlife, birds and flowers. It can still provide a sustainable livelihood, being a skill that land owners are pleased to pay fro, together with a renewable crop produced from the natural source.
A note for your diary: the 2017 National Hedgelaying Championships will actually be held at Stourhead on Saturday 28th October. A great event for anyone with an interest in rural skills and traditions.