A garden plumbing question....

Turned the water stopcock on to my external water tap yesterday and for the 3rd year running the copper pipe has split. The pipe was lagged,, I drained the pipe (or so I thought), left the tap open, and switched the water off inside the house, but yet again, a 1cm split. It there anything I can use instead of thin copper? The water comes from the house in a black rubber pipe, then there's a copper pipe that is attached to the garden wall, with the hosepipe tap on it. Are there any winter-proof solutions please?