In a pot, add the water and the bullion cubes. Boil until bullion is completely dissolved.
In a large saucepan, saute green onion in butter 3 to 4 minutes or until soft. Stir in flour to form a smooth paste. Cook for 2 min. Gradually stir in broth and bring to a boil. Add asparagus, kale, and watercress; cover and simmer 5-7 minutes or until vegetables are tender. Allow to cool.
Use a hand mixer to blend until smooth. Add the heavy whipping cream, and sour cream and continue to blend until smooth. Heat on low until cooked through (do not boil). Season with the salt, and white pepper. Serve with a spoon full of sour cream.