Plant with edible flower heads (9)
I believe the answer is:
artichoke
'plant with edible flower heads' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for artichoke that I've seen before include "Thistlelike edible flower head" , "Globe, perhaps" , "Jerusalem, perhaps" , "Edible thistle-like bud" , "Globe vegetable?" .)