Just my 2cents on the Shampoo Ginger, mine do die back even down here in the "semi-tropics". We had a few nights down to the 40's last winter and that was the extent of our "cold" weather.
But the Shampoo Gingers are already starting to peter out, even though we've had really warm fall weather. A few nights below 70 starts them towards sleepytime.
I'm with Bob on the Hedychiums. Mine keep leaves all winter unless we get as low as 30's although they don't grow or bloom. Keep them in their pots in the basement, cool and a little water.
