Combine tart cherries, sweet cherries, dried cherries, sugar, tapioca, almond extract, and nutmeg in a large bowl; mix well. Let stand 15 minutes. (It is not necessary to thaw fronzen tart cherries before using.)
Line a 9-inch pie plate with half the pastry. Fill with cherry mixture; dot with butter. Roll out remaining pastry and cut into six strips about 1-inch wide and 10-inches long. Weave into a lattice pattern over cherries. Trim edges, pinching top and bottom crusts together.
Bake in a preheated 375°F oven 50 to 60 minutes, or until crust is golden and filling is bubbly. If necessary, cover edge of crust with aluminum foil to prevent overbrowning. Let cool before serving.