Your best bet to keep the seedpod going and its freezing outdoors, is to bring it in and keep it under lights or by a really sunny window. Keep it away from heat vents etc. It might keep the pod or it may even stop growing and continue growing the pod in the spring. It is iffy but it might work.

I had a cutting of Aztec Gold keep its pod and another one throw up an flower stalk (inflo) with no dirt! I had brought the cuttings into the laundry room so they could get a callous before planting them and then of course, forgot about them. They ended up between the dryer and the wall. There is a window next to the dryer. One day I walked into the laundry room and thought, wow it smells just like fresh peaches in here...it was the Aztec Gold Cuttings that flowered! lol.

The cutting that kept its pod, eventually lost it once I potted it up and it started growing again. I assume it put its energy into growing roots and ditched the pod.

If you bring it inside for the winter and notice that your Plumeria seed pod is continuing to grow I would give the plant a small amt of water, like 2 cups at the most, once per week.

If the seed pod is NOT getting larger and it sheds all its leaves, the plant is going dormant. I would not water it then. At that point it might or might not continue the pod in the spring. I have had them keep making pods in the greenhouse but those didnt lose their leaves.

As long as it isn't freezing yet, you can just leave the plumeria outside and just bring it in on cold nights. If you are getting lots of solid freezes etc, You might have to leave it inside. If its not too big you might opt to move it in and out. Many of mine are in the 12 ft range and grow all crazy so hard to move.

Great insights, thanks for sharing. For now, it is just dormant, getting water once a month, with no leaves. Fingers crossed until spring !🙏

The seed pod was «separated» from the tree, with some help from my 5yrs old...so curious about plants..😀! I kept the unopened pods in the tissue bag for about 3 weeks. 

It looks like I may have some mature seeds. 

Michael