Sure it would. They go dormant. Keep them dry and -some do this- even put it in the garage. A greenhouse though would cause them to stay in leaf longer and also cause them to flush much sooner in late winter. Once days get longer,they go by that in a warm greenhouse.

If the plant is not too heavy to move, get a hand cart and put it in the garage or in a shed. If immovable, old sheets or blankets draped over it on the nights that freeze will help. Laying the plumeria down on the ground, if possible, will take advantage of radiant ground heat. A drop light under the coverings will also help on the coldest nights. I have also used foam pipe insulation from the hardware store. The slitted foam is easy to slip over branches. Tape the ends of the insulation at plant tips to seal. Good luck!

I have also used small incandescent Pin style Christmas Lights and then covered the plant with some old fitted sheets and tarps if there was wet weather expected.

I've used socks on each growing tip to ward off frost.