From the top of Davidson Mesa in May the Flatirons stand up sharp and the whole valley below has gone green almost overnight. Meadow Pro LLC works down in that green, mowing, edging and trimming lawns through Louisville's neighborhoods while the growing is at its most enthusiastic. Grass here comes on in hard bursts after the spring storms — a lawn can go from dormant to shaggy in ten days — so keeping ahead of it is most of the craft. That means a consistent height, a clean line where turf meets walk, and no windrow of clippings left behind on the concrete. By the time the truck pulls out, the yard looks effortless, which is the part that takes the effort.