An overwatered bougainvillea will have wilted, drooping leaves. The flowers may also be fewer in number and less vibrant than normal. You may also see brown or yellow leaves, which is a sign of leaf scorch. If you think your bougainvillea has been overwatered, check the soil to see if it is soggy or waterlogged. If it is, reduce watering and allow the plant to dry out somewhat between waterings.