"The Flowers of the Thorn" in Welsh "Blodam Drain" or "Blodau'r Drain" is a Welsh air in 3/4 time and A Minor. The parts are played AAB.
It is a Welsh air sometimes employed as a waltz. Classical composer Franz Joseph Haydn composed a song setting of the tune, with words that begin "How fondly I gaze...".
It was printed in Hamilton's Blodau'r Grug: 100 Popular Welsh Folk Dance Tunes (1992) and Matthiesen's The Waltz Book (1992).