Maybe the extra cold winter froze them in the smaller pots.

It was a zone 5 winter here in zone 6, and unmulched pots are susceptible to winter kill.

I lost my dahlias that way also. Previously, I had left them in their containers and they came back just fine for the last 2 years, and this was the year I was going to divide them in early spring. I dug and dug in that container and found nothing, not even mush. Now I'll take other steps to protect them in the winters (as well as the other option of taking them out to store before winter!)

You were lucky to keep Dahlias 2 years in pots. Dahlias are much more cold susceptible than Narcissi. In my zone we have to lift Dahlias but never Narcissi. In colder areas even Narcissi can freeze in containers.

Lesson learned.bI agree this was a very cold winter for us.Not much snow but ice. I am sure drainage and temps got them. I need to plant in the ground, next order. Then protect from squirrels. Thanks everyone for input.