Plant with edible stems (7)
I believe the answer is:
rhubarb
'plant with edible stems' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for rhubarb that I've seen before include "Reddish stalks - word repeated to simulate conversation" , "bitter stuff" , "Plant with fleshy reddish leaf-stalks used like fruit" , "Plant stem used as fruit" , "Stalky fruit" .)