hedge school

A school in the country parts of Ireland conducted in the open air, under the shelter of a hedge, while a rude schoolhouse, to which the name was transferred, was being erected for the accommodation of the children. Now universally used in a depreciatory sense. "You talk with contempt of a hedge-school. Did you never hear of a nate little spot in Greece called the Groves of Academus?" -Car let on Traits and Stories; The Hedge. School.