High Street in June is a corridor of Federal doorways and old maples, and the lawns beneath them are small, particular, and impossible to fake. JMJ Gardens tends that kind of ground in Newburyport — mowing to an even height, trimming around granite steps and iron fence posts, running an edge along the brick walks so the line reads clean from the sidewalk. Spring cleanups pull the winter's grit out of the beds; fall cleanups take the leaves before they mat down over the turf. Yards in this city are mostly seen from the street, and a dooryard cut well is a small gift to everyone walking past.