Possible Clues:

• Flower to fade, one fading with a small lump inside
• Vienna divider
• Vienna's ''blue'' river
• Auden adaptation about 'Black Flower' traveling through 10 European countries
• River flowing through Vienna
• Strauss's blue 15
• 'The Blue ___' (Strauss waltz inspired by a river)
• Bad painting taking in north European river
• Pest you’ll find on this flower
• Copenhagen citizen maybe eating grub half ignored famous river