Add the plums and water to a medium saucepan and cook over medium-low heat for 5 minutes.
Turn down the heat to low. Add in the blueberries and spinach to the top of the plums, do not stir. Cover and let cook for an additional 3 minutes. Remove from heat, let cool slightly.
Using slotted spoon, place blueberries, plums and spinach into a blender or food processor, leaving behind any extra liquids. Reserve extra liquids.
Add the cilantro into the blender or food processor and puree for 1-2 minutes until you reach your desired consistency, adding in resereved water in tablespoon increments if needed.