I'm not sure if you can say which waltz is more popular, yesterday's The Blue Danube or Tchaikovsky's Waltz of the Flowers, but I bet the two waltzes would run neck and neck. Waltz of the Flowers is only one song from Tchaikovsky's ballet, The Nutcracker, which premiered in December 1892. Waltz of the Flowers is one of the last pieces to be played in the ballet, followed only by Pas de Deux: Adagio and the Final Waltz and Apotheosis. Of course, the recent popularity of The Nutcracker (since the 1960s) is largely due to the ballet being performed every year around Christmas. (Ironically, yours truly has never watched the ballet.) Several of the songs, including Waltz of the Flowers, were also used in the popular Walt Disney movie, Fantasia.