I purchased BLUEGRASS MUSIC from Maryott's Daylily Garden this summer. They are closed right now but should start selling again (online only) by March -- although they don't start shipping until around June 15th. Here is the link if you're interested. You should check it out, as they have really fantastic plants!
Go down to "Keyword Search" and type in Bluegrass Music and hit enter -- and voila!
You could also google "Bluegrass Music daylily" and it should show other sources. But Maryott's is my favorite one because they give so many fantastic gift plants with your order -- even new introductions!
I hope you can find one!