The most common and most likely answer to this crossword clue is the 9 letter word NARCISSUS
I've seen this crossword clue in The Times
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More clues leading to the result NARCISSUS
- Plant South American’s in charge of managed the wrong way
- Drug agent is above suspicion in plant
- Drug agent is suspect plant
- Drug agent I figure out on reflection is a plant
- Susan cries out, dropping end of blue flower
- Bloomer as drug agent sends out missing drug
- One of a poetic host‘s urns is cast almost sloppily
- . Drugs cop is Southern American chap with a high opinion of himself
- Plant providing food served up around island close to South America
- He fancied himself a handsome chap in bed
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 = narcissus.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.
What does NARCISSUS mean?
NARCISSUS noun- Any of several bulbous flowering plants, of the genus Narcissus, having white or yellow cup- or trumpet-shaped flowers, notably the daffodil
- A beautiful young man, like the mythological Greek Narcissus