To a large dutch oven over medium heat, add the oil. Add the garlic, onion, carrots, and celery to the pan. Cook, stirring often, for 3-4 minutes until onions are translucent. Stir in the ginger, turmeric, rosemary, thyme, salt, and pepper and cook another 90 seconds more. Pour in the broth and bring to a boil. Reduce heat to medium-low and stir in the couscous. Cook, stirring occasionally, 15-20 minutes, or until the couscous and carrots are tender. Stir in the shredded turkey and peas, and cook until heated through, about 2 minutes more. Remove from heat and add more salt and pepper, if needed.