Boy, I wish I could answer for you. I grow most of my daylilies in pots but the zone difference is just too great between my zone 7 and your zone 4. If I was a gambling lady, I'd guess no. I would think the pots would freeze just too hard for the crowns to survive. Now of course, you could shelter them and they might survive, but I sure do doubt it.

OK, all you wonderful folks that brave the harsh conditions of the colder zones, please speak up. I'm out of my comfort zone(hehe) on this subject.

Blessings to you and to all, Mona

They can survive. The problem is that she lives in an apartment which makes it a little more difficult. Assuming she has a balcony. She can build a cold frame out of small bales of hay or use rigid foam insulation. Let pots freeze up and then place inside cold frame and fill with mulch or leaves. Put pieces of wood on top and drape with plastic. If she an extra fridge, she can put them in there. If a friend has an unheated garage, Stack them in a corner. I used the cold frame and the garage method last winter and never lost any plants.