Scarlet begonia is the common name for the begonia coccinea Hook, a species of the genus Begonia L. in the begoniaceae family. As the name implies, the flowers that bloom on this begonia plant are a brilliant scarlet red in color.
Members of the genus Begonia L. begonia are flowers that grow as perennials in the United States, in the states of Florida, Georgia and Hawaii and in Puerto Rico, according to the USDA Natural Resources Conservation Service. The begonia coccinea Hook, or scarlet begonia, is native to Puerto Rico.
Although scarlet begonias are not native to the U.S., gardeners can grow the plant throughout the country. In USDA Plant Hardiness Zones 1 through 7 grow it as an annual and dig the tubers up in the fall, or grow it in any kind of pot and bring it inside before the first frost. The scarlet begonia will grow as a perennial garden plant in warm weather states such as Florida, Georgia and Hawaii and elsewhere in zones 8 through 11.
There are other species of begonias that have scarlet flowers, including the Ambassador, Senator, Expresso and Varsity series as well as the Olympia Salmon Scarlet and the Volumia Scarlet begonias. However, despite the fact that those begonias all produce scarlet blooms, references to the scarlet begonia mean the species begonia coccinea Hook.