Preheat oven to 425 degrees. Place racks on a work surface. Using a sharp knife, cut a third of the way through the meat between every two rib chops. (This will help the roast bend and stand upright.) Using a trussing needle and cotton kitchen twine, tie the ends of one rack to the ends of the second rack, being sure that the meat side of each rack faces outward. Tie a second piece of twine around the crown directly below the rib bones. Season with salt and pepper; let stand at room temperature for 30 minutes.
In a small bowl, combine olive oil, zest, garlic, parsley, and sage; rub herb mixture evenly over meat. Transfer roast to a flat rack placed in a large heavy-duty roasting pan.
Roast for 15 minutes; reduce heat to 375 degrees and continue roasting, rotating halfway through, until meat is well browned and an instant-read thermometer registers 140 to 150 degrees, about 2 hours 15 minutes. (Insert thermometer into meaty center of crown, avoiding any bone. Take several readings to ensure roast is cooked all over.)
Remove from oven; let stand 20 minutes on the rack before transferring it to a serving platter. Remove twine and fill with cooked Wild Rice Stuffing. Garnish with rosemary and plums.