They do well here in Pennsylvania planted outside, and come back each year. Winter temperatures here can go down to zero degrees F.

If they will not overwinter indoors, they may need a period of dormancy or cold.

Why not keep one inside for a few months, then plant in a sheltered spot outside? When your clump is large enough, you can experiment with offshoots.

I'm one zone warmer than the above poster and I've never seen one indoors, unless it was an indoor courtyard setting without any temperature controls (more common in the south). It's a great container plant......easy to divide in early spring.