The tuberous begonia stores food in its roots. At the end of the growing season, the stem and foliage slowly die back and the bulb stores up nutrition. If the bulb is dug up before the foliage dies back, the bulb may die or may not bloom for several years.
The tuberous begonia prefers filtered sunlight or light shade. In full sun, the begonia suffers foliage burn and blooms poorly or not at all. In full shade, your begonia may grow lush foliage but not have enough sun for blooming.
The tuberous begonia suffers flower bud drop if it is overwatered or overfertilized. The plant needs moist soil that dries between waterings. This reduces disease and encourages blooms. The begonia benefits from application of a water-soluble balanced fertilizer once or twice a month.