Park Hill's streets climb in switchbacks past deep porches and yards that tilt toward the river. Mowing a hillside lawn is a different craft from mowing a flat one — you learn which way to run the passes so the grass lies down in one direction and the whole slope reads as a single sheet. Bella's Landscaping mows, trims and cleans up yards across Yonkers, taking on the awkward corners and stone steps that come with a city built on hills. By late afternoon the light arrives sideways off the water and every fresh cut looks like velvet. That is the part worth doing well.