Preheat oven to 350 degrees.
In large bowl, whisk together flours, sugar, baking powder and soda, ginger and salt. Add cold butter and cut in with a pastry blender until mixture resembles wet sand.
Mix together the mashed banana and sour cream in a separate bowl. Add to the butter and flour mixture and stir gently with a wooden spoon.
Turn dough out onto a lightly floured surface and sprinkle the top with the frozen blueberries and a light sprinkle of flour. Gently knead the dough until it comes together and blueberries are mixed in. Dough will be crumbly. Use a bit more flour if too sticky.
Use a light hand and press into a 7-inch disk. Gently cut into 8 wedges with a pizza cutter.
Place cut scones evenly on a baking sheet lined with parchment paper or a silicone baking mat.
Bake for 20-25 minutes, rotating pan once during baking time, until scones are lightly golden.