Blossoming after score in rugby test (3,3)
I believe the answer is:
try out
'test' is the definition.
(try out can mean to test or trial)
'blossoming after score in rugby' is the wordplay.
'blossoming' becomes 'out' (I've seen this in other clues).
'after' is a charade indicator (letters next to each other).
'score in rugby' becomes 'try'.
'out' after 'try' is 'TRY-OUT'.
(Other definitions for try out that I've seen before include "Sample" , "Put to experimental use" , "Test and evaluate" , "Taste" .)