The most common and most likely answer to this crossword clue is the 6 letter word DANUBE
I've seen this crossword clue in The Times
D
A
N
U
B
E
More clues leading to the result DANUBE
- Pest you’ll find on this flower
- Hairstyle with another flipping English flower
- Flower buried in cobweb unadvisedly picked up
- Spot European clutching new flower in Budapest
- Bad painting taking in north European river
- A U-bend unusual in river
- Dicky Benaud is one going from Vienna to Belgrade
- U-boat’s leader found floating in European river
- River god is lost – captivated by heartless Danae
- Bad painting featuring Northern European river
Buddy explains!

The straight part
We know that "flower" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case flower = danube.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.