I have ( in Dallas, Texas) Louisiana Bog Iris. I leave them in the
pond over winter & have for the past four years. They double & triple,
although this year was a bit colder than ususal so I put them in a tub
in the greenhouse.

I know that it is hard not to feed your fish when they beg but do not
feed them until the water reaches in the 50's. The can not digest the
food and it goes strait through them, The water becomes high in
nitrogen thus killing them or any baby frys.