Preheat oven to 425.
Mix crust ingredients in a medium sized bowl and stir to combine and form into a dough. Roll out on wax paper and press into a greased 9 inch pie plate.
Pour the chopped rhubarb and blueberries into the crust and gently toss to mix them together.
In a small bowl stir together the remaining filling ingredients and spread evenly over the rhubarb and blueberries.
In a medium mix together the topping with a pastry blender or fork until crumbly. Spread on top of the filling. Cover the pie with foil.
Bake for 45 minutes. Remove the foil and bake 10-15 minutes longer until topping is browned and the filling is bubbling. Enjoy!