October dusk over New Haven, the light going amber along the East Rock ridge, and the mowing season has one or two good weeks left in it — that in-between stretch is when Skyline Landscaping is busiest thinking ahead. Through the warm months the work is lawn care: mowing kept on schedule, the grass held even, the yard tidy from the street. Then the year turns and the same trucks go out for snow, clearing what the storm laid down so a driveway is passable and a walk is safe to cross at six in the morning. It is honest, repeating work in a city built on ridges and harbor wind, where one property can catch the sun all afternoon and the next stays frozen in shadow until noon. Skyline works both kinds, all year, in New Haven and the towns around it.