Preheat oven to 375 degrees.
Line a baking sheet with parchment paper.
Sift together the flour, whole wheat flour, sugar, baking powder, baking soda and salt into a mixing bowl.
Cut the butter into small cubes, then mix into the flour mixture with a fork until it forms small crumbs.
Add egg, buttermilk, lemon juice and lemon zest to the bowl and mix with a fork or your hands until a dough forms.
Gently fold the blueberries into the bowl.
Pat mixture into a disc, then slice into six pieces and bake on the prepared baking sheet for 15-18 minutes.