Abstract: A method (100) of mounting a blade (22) to or unmounting a blade (22) from a rotor hub (20) of a wind turbine (10), the wind turbine (10) comprising a tower (12) and a nacelle (16) mounted on the tower (12), the rotor hub (20) being coupled to the nacelle (16), the method (100) comprising gripping the blade (22) using a gripper (50), the gripper (50) comprising gripping members (58) configured for gripping the blade (22) and teeth (60) protruding from the gripping members (58), wherein gripping comprises inserting the teeth (60) of the gripper (50) into receptacles (78) of the blade (22); and rotating the blade (22) about a rotation axis (54) perpendicular to a longitudinal blade axis (53) using a blade rotation device (52) of the gripper (50), wherein the teeth (60) are configured for transmitting an axial load (57) of the blade (22) between the blade (22) and the gripping members (58).