During the winters, your Bougainvillea can get damaged. There will be dead branches that need to be pruned down. This needs to be done so that the living tissue surfaces again and the plant gets rejuvenated. If your plant is excessively damaged, it needs to be pruned right above ground level. Without taking out the living tissue, the plant will not reach its rejuvenation process. However, this needs to be done when the winter is over, and the blooming season arrives.