Certain dealers also sell named varieties grown from stem cuttings, such as 'Avalanche', 'Bonfire' and 'Falstaff'. In this country, these tubers are available from White Flower Farm. Many gardeners shy away from tuberous begonias because of their reputation for being difficult to grow. They really aren't. Although travelers discovered the ancestors of these beauties in the Andes Mountains in the mid-nineteenth century, more than half of the United States has microclimates or growing conditions that can sustain tuberous begonias.
Seed Starting Growing from seed rather than tubers is another option.
You can grow thousands of begonias from one small packet of seed. Begonia seed is powder-fine, however, and requires sterile soil and careful control of temperature to grow. And plant size, quality, flower color, and form are also unpredictable. The plants take six to eight months from seed to bloom. St. Louis was the biggest challenge because of summer heat.