overwintering Japanese Iris

I purchased some Japanese Iris in 4" pots. I have not planted them yet. It is getting too late here for them to get established. Can I keep them in the pots for the winter and how do I store them?

Yes, you can keep them in pots. Put them down in the ground up to the rim of the pot. Then mulch them with leaves, straw, whatever, around the pots (not over the crowns). But a big key is to keep them well watered until the ground freezes. Not frost, solid freeze.

4" pot is a very small pot for an Japanese iris. Get them out of there as soon as possible in the spring.