On August 31, 2012, at 1158 central daylight time, a Cessna 150M, N45080, registered to private individuals, contacted overgrown vegetation and veered off runway 04 while landing at the Blackhawk Airfield (87Y), Cottage Grove, Wisconsin. The private pilot, who was the sole occupant, was not injured. Visual meteorological conditions prevailed and a flight plan was not filed for the personal flight which was being conducted under the provisions of Code of Federal Regulations Part 91. The flight originated at 1125 from the Portage Airport (C47), Portage, Wisconsin, and the accident occurred at it's final destination (Blackhawk Airfield, Cottage Grove, Wisconsin). The pilot reported that the flight from Portage to Blackhawk was uneventful. Upon arrival to Blackhawk, he checked ATIS information which indicated that the wind was from 340 degrees at 6 knots. Since his runway choice was either 27 or 04, he decided to land on runway 04 since he had not landed on that runway in a long time. After a normal approach, the pilot landed the airplane just slightly left of centerline but did not think that it was overly to the left. As the airplane coasted to taxi speed, the left wing contacted high vegetation and overgrown brush overhanging the left side of the runway. The airplane then veered to the left off the side of the runway and crashed into brush and small trees, resulting in substantial damage to the leading edges of both wings. An FAA inspector who examined the site of the accident reported that there was high vegetation, up to 12 feet tall, overhanging the west side of the runway by 2 to 4 feet. High vegetation was also overhanging the east side of the runway by 1 to 3 feet. The published runway 04 width is 57 feet, but the usable area for landing was narrowed by approximately 7 feet due to the overgrown vegetation. The pilot stated on NTSB Form 6120 that he should have landed on runway 27, knowing that it was clear of vegetation on both sides. He said that he was not aware of just how much brush had overgrown the sides of runway 04 since the last time he landed there a few years ago. He stated that the left side of runway 04 was heavily overgrown and that a notice should have been given to alert pilots that the runway 04 width is narrower than its published usable width. He stated that if he had made a more perfect landing on centerline and rolled out on centerline, that the wingtip of the airplane would not have contacted the overgrown brush. Currently, the published information for Blackhawk Airfield includes information stating that brush and vegetation surround the edges of runways 04/22.