The last time I was in Hawaii (Oahu), I took cuttings of Bouganvillea growing along the roadside in Mililani – white, orange, bright pink, red – the colors were gorgeous. I trimmed away the leaves from the six inch twigs, washed them thoroughly, dried them out and brought them home. I was able to root successfully four of the ten and they grew for a while. I gave two to a friend and this is the sole surviving plant.
It over-winters in her greenhouse successfully. She’s discovered that the way to get the plant to bloom is not to water it through the winter, and only a wee bit when leaves start to appear in the spring. This is the display she has got this year.