Sweet expression of disapproval about fine flower (9)
I believe the answer is:
candytuft
'flower' is the definition.
(candytuft is a kind of flower)
'sweet expression of disapproval about fine' is the wordplay.
'sweet' becomes 'candy' (candy is a kind of sweet**).
'expression of disapproval' becomes 'tut' (I've seen this before).
'about' means one lot of letters goes inside another.
'fine' becomes 'f' (abbreviation).
'tut' going around 'f' is 'tuft'.
'candy'+'tuft'='CANDYTUFT'
(Other definitions for candytuft that I've seen before include "Garden flower" , "Catty fund (anag) - flower" , "Garden plant" .)