At the hedgelaying competition someone asked me when the first hedges were made in history.
It’s hard to give a definitive answer to this – there is evidence of British field patterns that go back at least to the Bronze Age (for instance Zennor in Penwith), though these are as likely to be separated by banks as by hedges (in Cornwall, a “hedge” can be a stone-faced bank without any plants on it).
Some hedges are “assart hedges” meaning they date back to the original forest clearance and contain species that don’t generally grow outside of woodland. The age of such hedges varies, but the clearance of the wildwood goes back even further than the Bronze Age, to the neolithic period, about 6000 years ago.
My suggestion in the book is that the first hedges were neolithic – they had advanced woodcraft skills in this period as can be seen in the woven wood screens they used for buildings (“wattle and daub”) and other structures. This means they knew how to coppice wood, to cut trees back in order to use the flexible new growth that results. So at the very least they would probably have made “dead hedges” out of wood.
But dead hedges tend to turn into live ones as some types of wood reroot and other new plants grow in the protection of the barrier. And live hedges are much more effective than dead ones, so it seems probable that live, coppiced hedges would have been cultivated in this period. The skills of coppicing and weaving wood are close to the “pleaching” process used in hedgelaying, so they may well have laid hedges too.
(We do know that by the Roman period hedgelaying was in use in Northern Europe as Julius Caesar describes the Nervii tribe using their laid hedges as military defences against his army).