The “Blackberry Blossom” most commonly heard today — a fast G-major breakdown, AABB form, with a B part that swings briefly into E minor — descends from a recording made by Fiddlin’ Arthur Smith in the 1930s. Smith reworked the tune from older versions he had heard, and the modern fiddle setting was effectively his composition. (Smith himself played the B section in E major; the E-minor coloring most pickers use now is a later evolution.)
Confusingly, there is also an older, unrelated tune called “Blackberry Blossom” — sometimes called “Garfield’s Blackberry Blossom” to disambiguate — with documented Civil War-era roots in eastern Kentucky. The folklorist Alan Jabbour traced the older version to a setting by Santford Kelly of Morgan County, Kentucky, a relative of the tune now widely known as “Yew Piney Mountain.” Smith’s reworked tune effectively supplanted the older one in the broader fiddle tradition.
The tune’s adoption into bluegrass owes much to Bill Keith, who joined Bill Monroe’s Blue Grass Boys in the early 1960s and developed a melodic three-finger banjo style that could play fiddle tunes note-for-note. Monroe demonstrated “Blackberry Blossom” in his mandolin workshop at the first bluegrass festival at Fincastle, Virginia, in 1965, and from there the tune entered the standard jam-session repertoire, where it remains a showcase piece for fiddlers, banjo players, and flatpickers alike.