Calling Blue Skies a bluegrass album is like focusing on a single color in a rainbow. The style informs everything Mountain Heart do, but they’re just as likely to dig into blues (“Miss Me When I’m Gone”) or soul-inflected Southern rock (the title track). Ironically, the closest they come to straight-up bluegrass is on a cover of Bob Dylan’s “Maggie’s Farm,” but the hard-charging instrumental “The Bad Grounds” shows that Mountain Heart are sporting some serious picking chops; just don’t expect them to stay in one place too long.