Bring water to a boil in a large pot; stir in red dates and goji berries.
Heat oil in a skillet over medium heat. Cook and stir carrots, ginger, and salt for 1 minute. Transfer to the pot of water. Stir in vegetable stock powder, sesame oil, and black pepper. Reduce heat to medium-low and add watercress; simmer until wilted, about 15 minutes.