Hedgerows traditionally were used as fences between fields, and a “laid hedge” in England contained thorny plants like hawthorn to act as a barrier. Cut through the lower trunk and laid over, each one crossing the next – this living fence was maintained by a hedger who would do this hand work during the winter. This was an actual full time job in days gone by.
When the plants sprouted, they formed a prickly barrier that was supposed to keep livestock in and presumably other people’s animals, or perhaps predators, out. Wildflowers and herbs would sprout up, aided by birds that perched and dropped berries and seeds below, helpfully packaged in poop to provide nutrients for the sprouting seeds.
The great thing about hedgerows aside from the barrier thing, was the diversity they provided. Pollinators, predatory insects, lots of animals and plants found refuge there and were a benefit to their surroundings, providing what we now call ecosystem services – now that we are losing those services and have come to recognize their true value.
Anyhow it’s easy to plant a hedgerow. I planted The one pictured by putting in way more vine maples (Acer circinatum) and red flowering currants (Ribes sanguineum) than necessary. Also lots of bleeding heart (Dicentra formosa), and miscellaneous other herbaceous plants and ferns (Polystichum munitum, Polystichum braunii, Asplenium trichomanes, Penstemon sp., etc).
I have pruned for shape, but so far not much else. The birds love it, insects galore, and it makes a nice wall to an outdoor “room”.