In a large pot, add all ingredients except maple syrup and bring to a boil. Reduce heat and simmer until vegetables are very tender.
Carefully transfer soup to a blender and puree until smooth, blending in batches if needed. Pass puree through a fine mesh strainer. Wipe out the pot that was previously used, then add the soup back to it.
Return to heat, bring to simmer, and add the maple syrup. Simmer until soup is thickened to desired consistency.
