The Lawn, like the Sandwich, is named for the aristocrat who invented it. Before Sir Walter Buffalo of Lawn decided that grass was better if let grow no taller than one inch, grass in Kent was allowed to grow to any height.
The grass in places was so tall as to hinder Northumbrian peat merchants from being able to see from bog to bog. Sir Walter was the first person to pay the local peasants who milled around the marketplace to cut a defensive perimeter of grass low enough that the Kentish forces (very short people at the time) could be seen from a distance. This innovation let to the counter-innovation of Topiary.
The story of Earl Topiary is for another time.