How can you keep a squirrel out of your flowers?

Well, usually, rats come because of food lying out in your house, and other things, so just keep your house nice and clean. There is also this little thing that keeps rats out that makes a relly high-pitched noise that rats can hear (and humans can't) that makes them leave or not go into the room its in. DON'T USE RAT POISON, it can kill any animal or human that eats it, and plus, who would wanna put rat poison out, then forget, then find a rotting dead rat behind their couch?