Bring first 6 ingredients to a boil in a large pot. Cover, reduce heat and simmer 15-20 minutes or until vegetables are tender. Remove from heat, and stir in corn.
Melt butter in a heavy saucepan over low heat; add flour, whisking until smooth. Cook 1 minute, whisking constantly, Grandually wisk in milk; cook over medium heat, whisking constantly, until mixture is thickened and bubbly. Add cheese, stirring until blended.
Stir cheese mixture gradually into vegetable mixture. Cook over medium heat, stirring constantly until thoroughly heated. Serve immediately. Garnish,if desired with some freshly chopped parsley.