Blossom's support (4)
I believe the answer is:
stem
'blossom's support' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stem that I've seen before include "Restrain - staunch - supporter" , "Main upright of a ship's bow" , "branch of family" , "Stop; stalk; ship's timber" , "Slender upright part, of flower or wineglass" .)