Sam Bush is the brilliant fiddler-mandolinist-composer who led New Grass Revival from 1971 through 1989. New Grass Revival’s dazzling instrumentals took bluegrass into new dimensions by fusing it with jazzy syncopation, extended improvisations, and rock ‘n’ roll energy. After the final incarnation of New Grass Revival broke up in 1989, Bush began a long string of guest spots on albums by the likes of Bela Fleck, Doc Watson, and Lyle Lovett. He also toured as a member of Emmylou Harris’ Nash Ramblers. But Bush is a guy with a restless muse, and in the late ’90s he decided to emphasize a solo career, which has already produced Glamour & Grits and this year’s Howlin’ at the Moon (both on Sugar Hill). These recordings are a logical continuation of Bush’s work with New Grass Revival; the bluegrass-jazz-funk fusion remains, though some tracks have a harder rock edge. To present his musical vision live, Bush has formed a new band, including bassist-vocalist John Cowan (a long time colleague in New Grass Revival), drummer Larry Atamanuik, and guitarist Darrell Scott. Catch Bush and company’s electric new grass grooves at 7:30 p.m. Friday, Dec. 4, at the Birchmere, 3701 Mount Vernon Ave., Alexandria. $20. (703) 549-7500. (Ken Roseman)