I think layout info can be translated easily to suite a southern garden, it's just a matter of switching out the plant materials for those that thrive in your area. For example, so many traditional Cottage gardens include Delphiniums and Lupines, neither of which will perform well here with summer heat and humidity. So instead I use Larkspur, Baptisia, Eremurus, and a few Hollyhocks to provide strong vertical lines. Where a northern garden may include Oriental Lilies, a southern garden may use Crinum instead.
