Confused Which Plantation to Visit in January for a mix of Gardens & History

Hello,

I am visiting Charleston with my wife in January and wanted to get an idea of the best plantation to visit. We are interested in getting to know more about the slavery history and also seeing some nice gardens/landscape. I am thinking of Middleton or Mangnolia but open to others and would appreciate some suggestions especially keeping in mind that it might my trip in January.

Also open to suggestions for other things to do for a winter trip. Thanks