Preheat the oven to 375 degrees F (190 degrees C).
Place spinach in a large glass bowl, and heat in the microwave for 3 minutes, stirring every minute or so, or until wilted. Stir in sour cream, pepperjack cheese, and garlic.
Lay the chicken breasts out on a clean surface, and spoon some of the spinach mixture onto each one. Roll up chicken to enclose the spinach, then wrap each chicken breast with two slices of bacon. Secure with toothpicks, and arrange in a shallow baking dish.
Bake uncovered for 35 minutes in the preheated oven, then increase heat to 500 degrees F (260 degrees C), or use the oven's broiler to cook for an additional 5 to 10 minutes to brown the bacon.