Exoticsflora Merry Palmer Bougainvillea thrives in full sun and needs at least 6 hours of direct sunlight per day for optimal growth and blooming. Well-draining soil: Bougainvillea prefers well-draining soil to prevent root rot caused by standing water. Sandy or loamy, slightly acidic soil (between a 5.5 and 6.0 pH level) is ideal.