Depends on the hardiness of the plant I suppose. At the nursery where i work, plants mainly shrubs and perennials are in pots and left to fend for themselves and we rarely lose any. It's more the long cold period mixed with wet that will kill them.
What plant is or perhaps was it!?

To add to Nicky's comments most damage to plant roots can occur with say regular freezing night time temperatures followed by continual thawing during daytimes