Posted: 10/11/2014 at 11:39
My experience is you can dry store them if the rhizome is big. If you grew from seed this year then store in slightly damp soil or they will tend to die They are bog plants in warmer climates.
I leave them to be lightly frosted basically to minimise the time they are stored for. You remove all of this years growth, being careful not to cut down next years growth, though it will continue to grow.
I just store them in the garage.