In the countryside hedges are one of Britain's most defining features, creating the lovely chessboard pattern you can see from a plane. Ecologically they are vital; thousands of species depend on them, and when they are grubbed up entire ecosystems are lost.
In towns and cities hedges allow us to mark out our territory; disputes over them can become shockingly heated. In the streets around me, with their 70s-style hydrangeas and dahlias, there's even the odd topiary throwback, like this wonderful house number:
Hugh Barker mentions a topiary whale just up the road from me in Brixton; sadly, an over-officious council ensured that it no longer exists. I would have loved to have seen it.
For more on Britain's hedges, click here.