Last Spring I separated out a potato vine, that I overwintered inside for 3 winters, into 4 containers. Each of these vines flourished and did very well. This fall, after they went dormant, I had planned on bringing them all inside but only brought one in and forgot about the other three containers. Now that we've had a severe freeze here in Chicago (many nights of single digit temps) I'm wondering if the potato vine bulbs outside buried in the containers are toast. Can potato vine bulbs survive a hard freeze? I'm wondering whether or not to bring them in now because the real cold weather, sub-zero temps, should hit here in January.