Barley vegetable soup

Ingredients

• 1 cup chopped onion
• 1/2 cup bias-sliced carrot
• 1/2 cup sliced celery
• 2 cups sliced fresh mushrooms
• 1 15-ounce can red beans
• 1 14.5 ounce can stewed tomatoes
• 1 10-ounce package frozen whole kernel corn
• 1/2 cup regular barley
• 2 teaspoons dried Italian seasoning
• 1/4 teaspoon ground black pepper
• 3 cloves garlic
• 5 cups vegetable broth