Berliner for one rejected colourful herb (9)
I believe the answer is:
germander
'herb' is the definition.
(germander is a type of herb)
'berliner for one rejected colourful' is the wordplay.
'berliner' becomes 'german' (I've seen this in another clue).
'for' says to put letters next to each other.
'one rejected' says the letters should be written in reverse.
'colourful' becomes 'red' (similar in meaning).
'red' backwards is 'der'.
'german'+'der'='GERMANDER'
(Other definitions for germander that I've seen before include "Plant of the mint family" , "Flower" , "European plant" .)