Leaves novelist on track (8)
I believe the answer is:
greenery
'leaves' is the definition.
(I've seen this before)
'novelist on track' is the wordplay.
'novelist' becomes 'greene' (Graham Greene).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'track' becomes 'ry' (abbreviation for railway).
'greene'+'ry'='GREENERY'
(Other definitions for greenery that I've seen before include "Trees" , "Leaves etc" , "fresh leaves on the tree" , "Leaves, maybe" , "Decorative boughs" .)