Why my Bougainvillea is not flowering properly

Hi, welcome to GoY, when you say,"not flowering properly" is it just getting a few flowers on ?, it needs a fertile soil, well drained and in full sun, try giving it a feed and see what happens, Derek.

The most common causes of poor flowering this time of year here in southern Arizona, Abbaspk, are lack of nitrogen and or potash, too cold nights, and too heavy pruning within the last few months. Many of the purple varieties of Bougainvilleas (B. glabra, and its hybrids) are reluctant to bloom in the winter, by nature.