Jardines de Mexico is an enormous botanical garden south of Cuernavaca, with long walking paths through themed sections including Japanese, orchid, cactus, and tropical gardens. It is one of the largest garden complexes in North America, so treat it as a half-day stop rather than a quick stroll.
The grounds are exposed in places and distances are bigger than they look on a map. Bring water and sun protection, or use the internal transport if you do not want to spend hours walking between gardens.