The pilot reported that during the landing rollout at the private airport, the glider's left wing struck a series of bushes located along the side of the landing runway. After striking the bushes, the glider swerved, exited the runway and came to rest in a ravine located along the right side of the runway. The glider sustained substantial damage to the right wing and aileron. The pilot reported that the airplane's wing span is approximately 60-feet and the width of the paved runway is approximately 50-feet, with a 10-foot shoulder on each side of the runway. The pilot reported the bushes were located approximately 900-feet from the landing threshold, were 4-7 feet tall, and 8-12 feet from the pavement edge on neighboring property to the north of his runway. In a written report, he indicated that there were no mechanical malfunctions or failures with the glider at the time of the accident. Following the accident, the neighboring property owner removed the bush.