Cordyline australis ‘Red Heart’ is sensitive to frost and is best overwintered in a cool place where the temperature does not fall below -3 to -5 degrees. Do water moderately. In the open ground it can survive mild winters outside with good winter cover (max. -10 degrees). Then take the leaves together and tie them and wrap the plant well. Also cover the bottom with a thick layer of mulch.

General care tips can be found here