Line a nine-inch pie pan with pastry dough, allowing a half-inch of crust to hang over the edge of the pie pan.
Put blueberries and rhubarb in a large bowl. In a small bowl, mix together sugar, flour, cinnamon and lemon zest.
Pour sugar mixture over fruit and stir gently with a rubber spatula until mixture is well distributed. Transfer to lined pie pan.
Use remaining dough for a lattice top. Fold the overhanging bottom crust back over the ends of the strips and crimp the pastry for a decorative finish.
Bake for, 15 minutes, then reduce heat to 350F and bake for 20 to 30 minutes, or until crust is golden and juices are bubbling.
Cool for several hours before cutting to serve.