Lorry governor used to carry agreed plant (9)
I believe the answer is:
artichoke
'plant' is the definition.
(artichoke is a kind of plant)
'lorry governor used to carry agreed' is the wordplay.
I cannot quite see how this works, but
'lorry' could be 'artic' (informal term for an articulated lorry) and 'artic' is found within the answer.
'agreed' could be 'ok' (eg when responding to an offer) and 'ok' is located in the answer.
'governor' could be 'he' (His or Her Excellency, address for a governor) and 'he' is present in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for artichoke that I've seen before include "Jerusalem or globe?" , "Jerusalem, perhaps" , "Thistlelike edible flower head" , "See 26" , "something to eat" .)