Something that's manicured is neat and tidy, like your neighbor's manicured lawn, with its perfectly trimmed grass and shrubs.
The adjective manicured is perfect for describing fingernails that have been cared for by an expert; when you get a manicure, your nails are manicured. But you can also use it for anything that's nicely groomed or trimmed, including your nicely manicured poodle, who's just been groomed, or your grandpa's orderly, manicured garden. The English word manicure comes from the French word manucure, which means "care of the hands," from the Latin manus, or "hand."