* Local Color was a popular movement, so many authors wrote in this style. To answer, we need a specific time period and region.
* "Southern" is broad: Is it the American South, or a particular state?
* "Writer" is also broad: Are we talking about novelists, short story writers, poets, etc.?
Here are some writers who might fit the bill, depending on the context:
* Mark Twain: While he wrote about the American South, his focus was often on the West and his style was more broadly American.
* Henry James: A major American novelist, James was more focused on the psychology of characters and the social dynamics of the wealthy, often set in Europe.
* Emily Dickinson: Her poetry, while often infused with the landscape of her New England home, didn't focus on the specific local color of the South.
To give you a more precise answer, please tell me:
* What time period are we interested in?
* Which specific region of the South are we talking about?
* What genre of writing are we looking at?
Once I have this information, I can suggest a more specific writer who wasn't a Southern local colorist within that context.