By mid-June the low ground near Beaver Brook holds its dew until the sun clears the oaks, and the grass grows fast enough that you can nearly hear it. Angel Landscaping & Tree Service cuts, trims and edges through that green rush, then keeps the beds mulched and the borders in shape as the season stretches out. Spring cleanups pull the winter off a yard; fall cleanups put it to bed. The reward is small and real — a lawn that looks cared for from the sidewalk, week after week, without anyone having to ask. Waltham comes first, with Watertown, Belmont and Newton close behind.