Plenty of things affect property values, but that doesn't mean that it's a criminal offense. A neighbor that lets his house go into foreclosure, a town that decides to put in a landfill just up the street from your house, a newer and nicer development opening a couple miles away, a shopping center closing up shop. None of these things result in jail time, I don't see how it is a remotely reasonable punishment.
Didn't these types of situations used to be handled with a neighborly visit or a friendly note mentioning that the yard was getting out of hand. I hate to see government intervention in situations like this.