Down at Innovation Hills the trail crosses the Clinton River on a slender suspension bridge, and the whole park is a lesson in how this city sits — woods, wet ground, and a river doing what it likes. The lawns above it still have to be cut. JGETZ Lawn Care Services keeps that side of Rochester Hills tidy with mowing, trimming, edging and the cleanups that open and close the season. Grass here grows in bursts, fast after a warm rain and stubborn in a dry August, so the route bends to the weather rather than the calendar. Leaving a yard sharper than you found it is a plain pleasure that does not wear off.