Our Bougainvillea from April onwards flower constantly well in to Autumn it really is very monotonous.
You do need to over-winter Bougainvillea indoors and give them a bit of a rest from all that flowering. They are best kept in a conservatory or any bright, open indoor space, keeping watering to a minimum so only give them water as the compost is obviously getting dry or the leaves start to wilt. Try to avoid temperature change when bringing them in and taking them back out again in Spring. See our Bougainvillea in it’s different forms here.