I have one large plumeria that has survived the temperatures ever since it was planted. There is also a rather enormous one at a neighbors house that is so elegant. Its blooms constantly and loses its leaves in the winter. Maybe I'm not really 9b, but every source I have looked at has said the same. Sorry to contradict...
We really dont get many freezes, and hardly any frost, maybe some frost in the dead of winter at record low temperatures but other than that it tends to stay above about 40 all winter.
Seed time again...
Microclimates and overhead protection from other trees can protect a plumeria from freezes. Just look at Davie's Arizona thread of a huge Singapore with overhead palms around it in Arizona. Also, very mature trees can often acclimate and sustain freeze damage to the branches without getting killed. It can be done, but typically, a plumeria out in the open without these protective microclimates will be killed at temps below 32. Microclimates are created by lots of things including large bodies of water, gravel instead of grass, proximity to concrete buildings, etc. These things help to warm the area by releasing heat and offer some protection from cold.
I think hardiness zones are based on low temp averages; for example, how cold it can get on average in a ten-year span. So, if you are above 40 at night for most of the winter, you are essentially Zone 10; however, if you get a killing freeze of, say, 28 once every ten years, that is enough to kill a plumeria, and that would make you Zone 9 regardless of what you usually have during the winter. Here's a good link of some rare cold damage in Zone 10: http://www.mauiplumeriagardens.com/forums/index.php?showtopic=10074&hl=damage
New to this site, but fell in love with plumeria about 3 years ago when a cousin gave me one. She even gave me seeds, but they never germinated for me. Someone gave me a rainbow one, but we had a bad frost and I lost several plants. I was going to pull up the remaining rainbow one, nothing happening for months, but about 6 months later leaves started appearing. I think I need more information on them, like watering, fertilizing, etc.
Samigal, there was a recordbreaking freeze here in Southern California the winter before last. I'm sorry to hear that you lost plants. I had some damage on mine that weren't protected.
Check out the Sticky Thread, which is the top thread on the Plumeria Forum. It has a bunch of information separated into categories: http://davesgarden.com/community/forums/t/599185/ There are also a bunch of friendly and helpful people here to help you with any questions that you have.
Thanks a lot Clare_Ca, will check out thread
It looks like I'm going to do a lot of reading on plumerias. I didn't know there was so much information out there. LOL
Clare
You will laugh but these are also three years old and in 7" pots. After your tips changed the pots and soil.
Kaleem
Hi Kaleem! It just shows how amazing these trees are! LOL! I think the growth has been stunted, but they should do much better with their new pots and soil. I think you will see a big difference in a year's time. You could even get blooms next year.