With two Australians and a Brit who formed their group in Austin, Texas before settling in Nashville, the Greencards play a version of Americana “bluegrass” that understands the tradition but isn’t afraid to break from it. Singer-bassist Carol Young is hardly your traditional mountaineer and adds a near ethereal mood to material that is mostly fired up with fiddles and mandolins. Producer Jay Joyce, who’s worked with an experimental artiste like Lisa Germano and a country-folk-rocker like Patty Griffin, indulges and informs the trio’s musical curiosities, adding an ambient touch to “Into the Blue,” providing the sonic room for Young to sing gently for “Three Four Time” and the chance for the entire group to showcase their chops from traditional instrumentals like “Little Siam” to the backporch rave-ups of “The Avenue” or “River Town.” Their unusual ability to take standard forms and twist them with an excited edge shows a versatility not expected from such a primitive setting.