Best time to transplant is when they are dormant. So now would be a good time. It may be tough to dig a hole if the ground is frozen. Good luck!

Most fruit trees are best dug and transplanted when they are dormant, but not in sub-freezing temperatures. Best times are in the Fall or early Spring. Paw Paws are an exception. The best time to transplant paw paws is Spring just as they are breaking dormancy (the buds are showing growth) and should be kept well watered until established. Take care digging them up as they tend not to be very forgiving of root damage.

I would not wrap these trees in plastic. Paw paws and walnuts can take below zero temperatures when dormant. The plastic will do no good.