Reject plant that’s in row (6)
I believe the answer is:
disown
'reject' is the definition.
(I've seen this before)
'plant that's in row' is the wordplay.
'plant' becomes 'sow'.
'that's in' is an insertion indicator.
'row' becomes 'din' (both can mean a loud disturbance).
'sow' put into 'din' is 'DISOWN'.
(Other definitions for disown that I've seen before include "Refuse to be connected with" , "Refuse to be associated with (something/someone)" , "Wins do (anag)" , "Deny any connection with" , "Repudiate, cast off" .)