Allow butter, eggs, and sour cream to stand at room temperature for 30 minutes. Meanwhile, preheat oven to 325 degrees F. Grease and lightly flour a 10 cup bundt pan; set aside. In a medium bowl stir together the 3 cups flour, baking powder, and baking soda; set aside.
In a large bowl beat butter with an electric mixer on medium to high speed for 30 seconds. Gradually add sugar, beating on medium speed about 10 minutes or until light and fluffy. Add vanilla. Add eggs, one at a time, beating on low to medium speed for 1 minute after each addition and scraping side of bowl frequently. Alternately add flour mixture and sour cream to butter mixture, beating on low speed after each addition just until combined.
Toss blueberries in the 1 teaspoon of flour. Gently fold the blueberries and lemons (zest and juice) into the batter.
Pour batter into prepared pan, spreading evenly. Bake for 75 to 85 minutes or until a toothpick inserted near center of cake comes out clean. Cool in pan on a wire rack for 10 minutes. Remove from pan; cool completely on rack. If desired, mix confectioner's sugar and lemon juice to make lemon glaze. Drizzle on top and serve.