In a dish large enough to hold whole cut up chicken, mix together the buttermilk, 4 sprigs of the rosemary, and the garlic. Add chicken, cover, and let marinate from a few hours to overnight in the refrigerator.
Mix 3 cups of the flour with the paprika, pepper, and mustard powder in a rectangular dish large enough to dredge the chicken. Drain the chicken from the buttermilk, and roll the wet pieces in the flour mixture.
Heat the oil in a deep sauté pan. While it is heating, coat the lemon slices with the remaining 1/4 cup of flour and set them aside.
Fry the chicken for 8-10 minutes, turning it to get even color. Then add the remaining rosemary sprigs, the sage, and the floured lemon slices to the oil and fry chicken, herbs, and lemon for another 7-10 minutes.
Remove the chicken from the oil and drain on paper towels. Season with salt and pepper, if desired, and serve with the fried lemon wedges and herbs.