An interesting historical hedge – when the Dutch were first settling South Africa, Jan van Riebeeck was Commander of the Cape from 1652 to 1662 and was in charge of the Forte de Goede Hoop (Fort of Good Hope). As part of the fortifications to keep the local population out he had a wild almond hedge planted. Part of the hedge still grows in the Kirstenbosch National Botanical Garden in Cape Town.
There’s a picture and more details here.
There are various historical cases of hedges being used as barriers , including the British Customs Hedge in India, used as a barrier to prevent salt smuggling, and the German use of Normandy’s hedgerows as cover in the post-D-Day “Battle of the Bocage” (bocage being French for hedgerow). I’ll write more on those later.
(Thanks to Duncan for telling me about this one. He’s also pointed out that the signpost on the linked blog post indicates that the Afrikaans words for fence and hedge are identical.)