Cover pork bones with water (3 inches above bones) and salt then bring to a boil. Simmer for 1 hour, making sure water level stays above the meat. Make doughboys by sifting flour and 1 teaspoon of salt together then add water to make a sticky dough. Set aside.
Remove fat from top of stock then add watercress and simmer for 20 minutes. Add potatoes, pumpkin and kumara.
Boil on high for 15 minutes then add the doughboy mixture in spoonfuls. Cook for 20 minutes until doughboys are done. Serve in soup bowls.
You can substitute any root vegetables and most kinds of meat.