Preheat your oven to 350°F (175°C). Grease and flour a bundt pan.
In a large bowl, combine the cake mix, buttermilk, vegetable oil, and eggs. Beat on low speed for 30 seconds, then on medium speed for 2 minutes.
Gently fold in the blueberries, lemon zest, and lemon juice.
Pour the batter into the prepared bundt pan and smooth the top.
Bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for 10 minutes before inverting onto a wire rack to cool completely.
While the cake is cooling, prepare the lemon glaze. In a small bowl, whisk together the powdered sugar, lemon juice, and milk until smooth.
Drizzle the glaze over the cooled cake.