I am sorry for this delayed reply to your gardening question. We are transitioning to a new Q&A system and your question was unfortunately lost in the transition. I have discovered it now and hope this reply is not too late to be of help.
Bougainvilleas can be troublesome in that way at times. They do like full sun and yours may be partially affected by the moderate amount of sun it is receiving. It is also important to keep them healthy but not to over fertilize them or they put their energy into growth and foliage at the expense of bloom production. Cut back on fertilizer and water enough to keep it going but not luxuriously growing. Give the plants only enough water each morning to prevent them from completely drying out. Don't worry if the leaves drop your bougainvilleas will still be okay. Continue this procedure for two weeks, then begin watering daily, and fertilize lightly with a product with a 3 1 2 ration such as 17 7 10 or 15 5 10. The plant should settle down and start blooming in time.
Some people take the drastic measure of root pruning to get their plants to bloom. This is done by forcing a shovel into the soil in 4 locations a foot or two away from the base of the plant, thereby cutting some of the roots. I would only do this as a last resort, such as if it wasn't back in bloom by next spring.
In Florida bougainvilleas should be pruned after the winter bloom, usually in February. Pruning consists of cutting back the lateral shoots of the previous summer's growth to within two buds of the base of the past year's growth. Without this pruning, there will be few blooms.
Bougainvillea blooms occur only on new growth, so new growth on plants is vital to the achievement of flowering. Bougainvillea normally flowers during the short days of winter, but blooms are highly dependent on temperature. Drought stress can also stimulate flowering even with long daylight exposure. Growers frequently allow plants to dry just to the point of wilting to induce flowering. However, excessive drying can cause leaf drop and dormancy; use care and be sure to water at first signs of wilt.
Thanks for the question. Please stop in again soon!
Q&A Library Searching Tips