Rose planted in west-facing flower garden (4)
I believe the answer is:
grew
'rose' is the definition.
(I've seen this before)
'planted in west-facing flower garden' is the wordplay.
'west-facing' says the letters should be written in reverse (letters written right to left or east to west).
'planted in' indicates a hidden word.
'werg' is hidden in the letters of 'flower garden'.
'werg' back-to-front is 'GREW'.
(Other definitions for grew that I've seen before include "Got larger" , "Rose" , "Got bigger" , "Became larger" , "Expanded - flourished" .)