Rising star gets a flower (4)
I believe the answer is:
avon
'a flower' is the definition.
(River Avon - something which flows)
'rising star' is the wordplay.
'rising' shows that the letters should be reversed in order (going up in a down clue).
'star' becomes 'nova' (nova is a kind of star).
'nova' reversed gives 'AVON'.
'gets' acts as a link.
(Other definitions for avon that I've seen before include "Shakespeare was known as the Bard of . . . ." , "River joining Bath with Bristol" , "Shakespeare its swan" , "River of the Bard" , "[WILTS] flower" .)