When Sarah Jarosz released her 2009 debut album, she was hailed as a teenage progressive-bluegrass phenomenon. But her reflective songwriting, silvery vocals and fleet-fingered musicianship draw just as much from folk, rock and pop influences. If she never sang a note, her prowess on mandolin, banjo and guitar would still be celebrated in the Americana realm, but she’s also a gifted singer with a lithe, nuanced style. Jarosz had an armful of Grammys before she was out of her twenties, both on her own and as one-third of supergroup I’m With Her, alongside Aoife O’Donovan and Nickel Creek’s Sara Watkins. Whatever the format, the Texan singer/songwriter retains her roots without being boxed in by them.