Cook bacon in large saucepan over medium heat until crisp. Transfer bacon to opaper towels to drain. Pour out all but 3 tablespoons drippings from pan.
Add next 4 ingredients to pan; sprinkle with salt and pepper. Saute until vegetables are crips tender, about 5 minutes. Sprinkle flour over; stir 1 to 2 minutes. Gradually add milk to pan, stirring constantly. Bring to boil; reduce heat to medium and cook until slightly thickened, stirring often about 5 minutes.
Add potatoes, clams with juice, and drained corn. Bring to boil; reduce heat to medium-low and simmer until potatoes are tender, stirring often, about 10 minutes.
Season to taste with salt and pepper.
Divide soup among bowls, sprinkle with bacon and parsley, and serve.