During landing on a private dirt strip, the right main landing gear broke through a large gopher hole, the airplane veered to the right, and before the pilot could correct the excursion, the right wing struck a sage brush along the edge of the runway. The airplane continued off to the right of the runway and impacted a soft berm and the airplane nosed over. The airplane sustained substantial damage to the rudder and to the left upper wing. The pilot reported no abnormalities with the aircraft prior to the accident.