Line a rimmed baking sheet with parchment paper; set aside.
Place the flour, sugar, baking powder, lemon zest, and salt in a large bowl and whisk to combine. Scatter the butter cubes over the flour mixture. Using a pastry blender or 2 knives and working quickly, cut the butter into the flour mixture until small, pea-sized pieces remain. Add the blueberries and toss to combine.
Drizzle in the buttermilk and mix with a rubber spatula until just incorporated and a rough, slightly sticky mound has formed (not all of the flour will be incorporated). Turn the dough and loose flour out onto a floured work surface and knead until most of the flour is incorporated and the dough just holds together (be careful not to overwork it).
Pat the dough into a 1-inch-thick-round about 7 inches in diameter. Cut into 8 wedges. Transfer the wedges to the baking sheet, spacing them evenly apart. Refrigerate for 15 minutes. Meanwhile, arrange a rack in the middle of the oven and heat to 400°F.
Bake until golden-brown on the top and bottom, about 25 minutes. Let cool 5 minutes on the baking sheet, then transfer to a wire rack to cool completely, about 30 minutes.
Whisk the powdered sugar and lemon juice together in a small bowl until smooth. Drizzle over the cooled scones in a zigzag pattern and let sit until the glaze hardens, about 15 minutes.