This is a Begonia species. Begonia are native to South America and are tropical plants requiring good moisture and frost free conditions. They are used extensively world wide as house plants and as bedding plants and also as perennial garden plants in tropical or nearly frost free areas. Thousands of hybrids are produced and available. They come in many shapes and colors.
Since there are so many different ones available, and they change varieties from year to year, we can only make an educated guess with this. It may be part of the new Non-Stop Series from Proven Winners. Sorry, but that is the best we can do.
If you know where it was purchased, you can ask someone in the annuals department, to tell you which “brands” they carried this year.