That red clay is not conducive to growing tomatoes with much flavor. Of course, so many of the US tomatoes are grown without flavor anyway. The best garden vegetables come from farther north - places like Michigan or Vermont. Even though the growing season is shorter there's something about the soil that makes them better. The same thing goes for berries in particular, but it works with other things. For example, I remember growing up in Iowa and finding out that all of our corn was "too far south" to be used for human consumption - it was all used for feed corn for animals or made into corn products like corn oil or corn syrup. Sweet corn grew better in Minnesota, Michigan, etc.