Either....Iris are tough as nails. I once bought an iris rhizom and put it in a cupboard and forgot it for a year....Planted it and it grew and flowered the second year.
But they probably would prefer to be in the ground over the winter.
Linda C

UI cricket, Lindac is right, they will do much better left in the ground, but if you move them before they bloom next spring you'll abort the bloom. So, put them somewhere where you can enjoy them and then after they bloom move them to a permanent home. :)

Diann
IA Z5a