Position a rack in the middle of the oven and heat the oven to 375 degrees F. Line a baking sheet with parchment. In a small bowl, mix 3 tablespoons of the sugar with the cinnamon.

In a large bowl, whisk the two flours, the remaining 1/4 cup sugar, the baking powder, orange zest, and baking soda until well blended. Cut the butter cubes into the flour mixture with a pastry blender (or two table knives) until the mixture looks like cornmeal with a few butter lumps no larger than peas. Stir in the cherries and walnuts. Add the buttermilk and stir just until no dry flour is visible; the dough will be wet and sticky.

Turn the dough out on to a lightly floured board and pat into a 1-inch-thick round. Cut into eight wedges. With a spatula, transfer the wedges to the baking sheet, spacing them about 2 inches apart. Sprinkle the cinnamon sugar over the scones. Bake until the tops of the scones are firm to the touch and the edges and bottoms are lightly golden brown, 18 to 20 minutes. Let cool on a rack. Serve warm or at room temperature.