Mature blossom? (7)
I believe the answer is:
develop
This clue is a double definition.
'mature' is the first definition.
(thesaurus)
'blossom?' is the second definition.
(blossoming is a kind of developing)
(Other definitions for develop that I've seen before include "Result" , "Grow, elaborate" , "Convert (land) to new purpose" , "issue" , "Grow, advance" .)