At Yantic Falls the river drops through a rock notch older than the city, then runs on cold and loud to meet the Shetucket below town. GroweTrees LLC tends the lawns on the ground above it, in a Norwich of front yards that tilt, deep-shaded side streets, and grass that has to earn its footing on a pitch. The work here is lawn care and lawn maintenance — the regular round, the cut kept even where the ground refuses to be. Mornings arrive over these hills damp and green, and a mower leaves lines you can read from the sidewalk. There is a plain satisfaction in that: a tended yard, on a street that notices.