Late summer loosens its grip on the Nashoba Valley, and the mowing changes character — slower growth, longer shadows, the deck set a notch higher for the cool weeks coming. Great Heights Landscaping keeps lawns in Ayer on that rhythm, working the yards that step down toward the old rail junction at Depot Square and out along the ponds, where grass runs right up to fence line and granite curb. There is a plain pleasure in a cut done properly: the passes laid straight, the edge along the walk clean enough to read, the clippings gone and the yard sitting quiet in the evening light. They mow, trim, edge, and clear away what each season drops, for households across Ayer and the towns that ring it.