Moving irises in the dead of winter

Please help with your expertise and tips for potting up and keeping irises alive in the winter. So many years invested in collecting plants and working my dream, over 500 cultivars, and now I'm going to be digging them up, moving them, and hoping they can survive winter outside in pots.

I have many inside in flats. This means they can root well. I'll plant out in the spring (May up here).

Is your ground frozen? Do you have green leaves still? If not frozen ground, so, you can write the name on the leaf and put quite a few into each pot.
inanda

I have too many plants and not enough space to bring them inside.