Singer, songwriter, and bandleader Ryan Montbleau — a Massachusetts native with a soulful style — leads his skillful sextet through an eclectic mix of old-school R&B, rootsy rock, and melodic folk-pop on their latest album, Heavy on the Vine. It’s an ear-pleasing concoction of Americana. “I’m not one of these people who say, ‘Oh, we can’t be pigeonholed,’” Montbleau says. “I honestly wish we could, just so I could describe it quickly to people. This record has folk songs, funk songs, country tunes, a reggae tune … and the end is almost like prog-rock. It’s all over the map, but it’s all us, and we do it all wholeheartedly.” The current lineup features drummer James Cohen, keyboardist Jason Cohen, bassist Matt Giannaros, violist Laurence Scudder, and percussionist Yahuba. They hit the main stage around 9:30 p.m.