It never works for me because rot always sets in but my mom seems to get away with it. Use really well draining soil if you do choose to pot them up. If your in a really wet area of the country like I am then adding alot of drain rock to the bottom of the pot would probly be a good idea.

I agree, pots should work, if they have good drainage. Sinking the pots in the ground might cause them to not drain as well though, imho.

The main thing in our zone, is that they are planted early enough in the fall, to put down good roots that will anchor them from heaving with the many freezes and thaws in the winter. I have planted too late before and learned my lesson when they heaved.

I've sometimes had rot issues with irises potted in garden soil (most likely from poor drainage). When potting them myself, I always use potting soil (something like Supersoil works fine).

Why don't you just dig them up, trim the leaves to ~6", dust off the soil and store them in a cool dry place until you can replant? They can be planted into the Oct timeframe with no ill effect depending on your zone. I bought iris in May last year and didn't plant them until Oct/Nov 2010 and for the most part they all bloomed and are all doing well.

A well placed landscape staple will keep them from heaving or pulling the rysom out of the soil when in bloom.