European flower festival (6)
I believe the answer is:
easter
'festival' is the definition.
(Christian festival)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for easter that I've seen before include "Teaser about Christian festival" , "Annual religious festival" , "Christian celebration of the Resurrection" , "Christian festival in Spring" , "Major Christian festival in April" .)