Plumerias go dormant at sometime in the fall until sometime in or after march when they spring back to life and begin to grow new leaves. If your stem is not mushy at the ground level and throughout the plant, it is problably shutting down for the winter. Water it only lightly once a month and keep it protected from frost or cold weather. When dormant it needs no light and can do with no water (many like the roots to have a bit of moist soil). It can be set in a room or garage as long as it does not freeze. Bill

Maxinep some of my plumie seedlings have gone into dormancy. I didn't realize that the young seedlings did this but they seem fine. I'm treating the ones that have gone dormant the same way that I'm treating my mature dormant plants, cool, dim and dry. The stems are nice and fat and the tips look healthy, just no leaves. It wasn't only my bigger seedlings either but an equal mix of tall & short ones. This was my first year growing plumeria from seed and I thought that I was losing them at first.
Karyn

Don't worry! I grew some from seeds last year too. I thought they were goners when they spent the winter bare-leaved and looking so sad in their 10 ounce styrofoam cups. But...:)...this spring when I put them in the ground, they grew and grew and grew. Some are now close to 2 1/2 or 3 feet tall and with multi-branching....and even one with an inflo! I was prepared to wait 3 years for a flower, but I think this must be a very happy mutant because it's trunk is huge (twice the size of the others) and super straight (while the others all have been curving or leaning!). This is my first full year with them, some were cuttings and some were seedlings. All the cuttings have grown at least 2 feet and branched out multiple times too and all have flowered. I didn't think it was possible so I've very pleasantly surprised!

Every fall all of my plumerias lose their leaves, and I just put them in my garage and forget about them. No water, no sunlight, no nothing! When it starts to warm up in the spring, I put them back outside. This year, I have one planted in the ground and plan on leaving it there to see if it can overwinter. My neighbors have one that has been in the ground for 20+ years, and it even survived the 2004 Christmas snow that we had.

I just got back from visiting with my daughter and her family in Hawaii, and I was so surprised to see all of the plumerias losing leaves and going dormant. I always thought that they only lost their leaves when it got cold, but obviously I was wrong, since it doesn't get cold on Oahu, and still all of them were losing their leaves.