I have day lilies in large pots, do I cut them down for winter?

If you have some freezing temperatures there then just leave them on. It helps to protect the the rhizomes /culms from freezing. I would also suggest to keep any freezing weather from penetrating the soil around them. If you can dig a ditch and bury the pots in the ground making sure to cover them back up with the soil and leave till spring. When you start to see new growth 5' to 6 " tall them remove the old tops.

I have a yard full of daylillies and Hakuro Nishi Japanese Dappled Willow, easy to maintain.

It is really up to you. If you want to see the stalks hang around for decoration, then leave them there. However if you think they are a bit ugly, cut them back after they have sent dormant. It does not hurt the plant one way or the other. They should be cut back before the new growth starts in the spring. Happy Gardening.

If you live in a freezing weather state, after you cut them to the soil line, wrap white "row covering fabric" around and over the top of the pot several times to keep them from freezing. I buy the row fabric at nurseries or gardening centers. It comes in a package and is 50 to 100 feet in length. It is easy to cut and will let rain and sun in. It can be used over and over again.

You can cut them back. The roots will continue to grow in preparation for spring.