Hey Nick1212,
In my zone, Houston, 9A or 9B, depending, I haven't brought most of mine indoors, ever.
No problems with freezing, even when it's been below 0 outside. Since I have the Automatic Watering System(AWS) connected, I do have to replace the pressure reducer every 3-5 years, but not sure if it is the cold snaps causing the problem. Also, I have always had more than 5 boxes connected to the AWS, which may mean that there's very regularly enough of a flow to keep the freezing from being destructive.
Texas.Micky