Some years ago in my nuclear power career I overheard something about mowing the grass. I didn't realize why it was such a big deal. The basic problem relates to security - higher grass provides cover for attackers. IMO the limits seemed overconservative, but maybe that's why I don't work in security.
Lately we heard about orchards in Iraq being cut down punitively. Or at least so it was spun in the media. The rest of the story is here.