Combine zucchini, carrots, mushrooms, onion and potato in heavy large Dutch oven.
Add vegetable broth, crushed tomatoes, stewed tomatoes, 3 tablespoons parsley, cilantro, garlic, basil and oregano.
Bring mixture to boil.
Reduce heat, cover and simmer until vegetables are tender, about 30 minutes.
Strain cooking liquid into large saucepan; reserve vegetables.
Place 3 cups vegetables in blender.
Add 1/4 cup cooking liquid.
Puree until smooth.
Stir puree into remaining cooking liquid in saucepan.
Return remaining vegetables to cooking liquid.
Season to taste with salt and pepper.
(Can be prepared 5 days ahead. Cover and refrigerate.) Bring soup to simmer.
Ladle into bowls.
Sprinkle with additional parsley.
Serves 8.
