Steam potatoes until done (about 10 minutes), then set aside. Place corn in oven with skin on and roast on 350 degrees F for about 20 minutes. Set aside and let cool. Cut corn off cob. Heat butter and sauté onion and celery. Add flour and stir and cook for 5 minutes. Add chicken stock and mix thoroughly, and then add remaining ingredients and seasonings. Bring to a boil, stirring occasionally. Remove from heat and serve.