@DeDePlumeria. I am also in a cold winter zone and just started growing some plumeria this year. My White , (stands about 3 foot now) started an inflow in Late August/early sept and bloomed for the first time on Sunday . Our nights are cold now so i bring it in at night and put under T5 grow lights until 10:00pm and start them off again around 7:00am. When the temps get about 60 outside i have been using a small 'green house' / cold frame for it to spend its day until sundown. The temps rise quickly in the mini-green house so i open the lid and ventalate enough to keep it around 90. I too wanted to see it bloom but having one start so late in the year certainly posed a challenge. Ken is right, warm temps and bright light will keep it going.
Ive attached a few pics. Good Luck !
