In summer the ski slope at Arrowhead goes green all the way up, a wide mown ribbon on the hillside above Claremont, and the city below takes on that same open, tended look. Marathon Property Services works toward it on a smaller scale — mowing, trimming, edging, keeping beds mulched and hedges shaped through the long middle of the year. Spring starts with a cleanup that clears out everything winter left; October ends with leaves cleared while they are still dry enough to move. Steady weekly cutting is what does it, the kind that never lets a lawn get ahead of itself. The result is a property that looks easy, which is the whole trick.