There are over 1,500 species of begonias. The American Begonia Society classifies begonias into several major groups: cane-like, shrub-like, tuberous, rhizomatous, semperflorens (or wax begonias), rex, trailing-scandent, or thick-stemmed. There are unusual in that they can frequently be hybridized with each other, and this has led to an enormous number of cultivars.

In temperate climates begonias are grown outdoors as annuals, or as house or greenhouse plants.