Whatever I plant under my evergreens dies even if watered.
Does Anything Grow Under Evergreen Trees?
Directly under an evergreen, or within a group of evergreens, generally you see nothing but evergreen needles. That's because the shade is so deep that nothing will grow. Under less dense evergreens, or somewhat out toward the edges of the tall growth, where the shade is less dense, you can experiment with other plants. You'll need things that will grow in shade, and acid soil. Here's an article listing many shade-loving plants: https://www.gardeningknowhow.com/special/shade/finding-a-shade-loving-plant.htm