Plant leased before truce? Not right (7)
I believe the answer is:
lettuce
'plant' is the definition.
(lettuce is a kind of plant)
'leased before truce? not right' is the wordplay.
'leased' becomes 'let'.
'before' is a charade indicator (letters next to each other).
'not' indicates named letters should be taken away.
'right' becomes 'r' (common abbreviation).
'truce' with 'r' removed is 'tuce'.
'let'+'tuce'='LETTUCE'
(Other definitions for lettuce that I've seen before include "Leaves eaten in salads" , "Salad green" , "Salad leaf" , "Salad stuff" , "Plant with broad crisp leaves used in salads" .)