Trim fat from pork, cut into 1 inch pieces. Combine flour and pork in a resealable bag, seal and shake well.
Heat 1 tablespoon oil in a large skillet over medium high heat. Add pork, cook 3 minutes or until browned. Remove from pan and keep warm.
Heat remaining tablespoon oil in pan. Add bok choy, celery, red pepper, mushrooms, water chestnuts and garlic; stir fry for 3 minutes. In a bowl combine chicken broth, soy sauce, cornstarch, sherry and ginger. Stir well with a whisk. Combine pork and broth mixture in skillet, cook 1 minute or until thick.