Bumbleberry pie  Bumbleberry pie is a Canadian mixed berry pie originating from the Maritimes. It is made of at least three kinds of berries, but generally refers to a mixed-berry pie, as there is no such berry as a "bumbleberry". This pie often also contains apple and/or rhubarb. Berries commonly used in this pie may include blueberries, raspberries, strawberries, and blackberries. See also: