Begonia
There are some 1500 species of begonias and, by some estimates, more than ten thousand named cultivars and hybrids. To simplify matters, they are divided by horticulturists into informal groups, based mainly on their growth habits.
Some tuberous begonias (especially those in the Tuberhybrida group) are used as bedding and border plants that must be lifted in autumn and kept dry during the winter if they are to see another summer. Unless new plants are to be sown each spring, the tubers should be dug up, dried, dusted with fungicide (flowers of sulfur is fine) and stored until spring when they are replanted, convex side down.
For tuberous begonias grown in containers in the greenhouse or as house plants, water must be withheld during the winter dormant period, but the tubers may be left in their pots. (Tip the pot on its side.) You can create larger flowers and prolong the flowering period of tuberous begonias by pinching out the two smaller female flowers that grow on either side of the male flower.
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