China possibly after auto plant (9)
I believe the answer is:
carnation
'plant' is the definition.
(carnation is a flower)
'china possibly after auto' is the wordplay.
'china possibly' becomes 'nation' (china is a kind of nation).
'after' is a charade indicator (letters next to each other).
'auto' becomes 'car' (synonyms).
'nation' put after 'car' is 'CARNATION'.
(Other definitions for carnation that I've seen before include "Pink/white/red flower" , "Pink - garden flower" , "Not in a car (anag) - plant" , "Oscar Wilde wore a green one" , "Feature of many a wedding" .)