Mooring charge coming from plant long time afterwards (7)
I believe the answer is:
dockage
'mooring charge' is the definition.
(I've seen this before)
'plant long time afterwards' is the wordplay.
'plant' becomes 'dock' (dock is a kind of plant).
'long time afterwards' becomes 'age' (I've seen this in other clues).
'dock'+'age'='DOCKAGE'
'coming from' acts as a link.
(Other definitions for dockage that I've seen before include "Berthing" , "Mooring charge" , "berth" .)