Looking back, the idea of Dolly Parton recording an unadulterated bluegrass album seems an obvious one. Still, it took decades for the country icon to get around to fully exploring the music of her native Appalachia on The Grass Is Blue (1999). This beautifully-rendered work both reaffirms Parton’s artistic standards and stretches the boundaries of bluegrass in creative ways. Connecting profoundly with the genre’s yearning sentiments, as well as its sly humor, she applies her voice to a diverse and well-chosen batch of songs. Reworking ‘70s pop/rock tunes like Billy Joel’s “Travellin’ Prayer” and Blackfoot’s “Train, Train” proves to be a boldly successful experiment — the latter particularly works as a galloping acoustic number. The folk standard “Silver Dagger” and Johnny Cash’s “I Still Miss Someone” are equally impressive as haunting mood pieces. From the playful “Cash On The Barrelhead” to the wistful “I Wonder Where You Are Tonight,” Parton is in command (and from the sound of it, having serious fun) throughout. Sterling performances by Stan Bush, Jerry Douglas and similar top-flight pickers contribute to the album’s excellence. Some things are worth waiting for.