I forgot to say:
Camille. My bad!
For the first time in many years I decided to leave a couple of dozen plumeria in their (large) pots and built a temporary greenhouse in the garage. It was about 8'x4'x8' and was built of 2x2's and solar blanket material, 16 mil. The solar blanket holds the heat in so well, that though we get into the 20's and occasionally the teen's, I used the smallest electric space heater I had and used it at its lowest setting. I did force all the plants into dormancy though. The seedlings I had (about a dozen) were overwintered in my "Everything Else" greenhouse since they were all in their first year and I didn't think they could survive dormancy.