Drive a wedge between established area of grass (8)
I believe the answer is:
estrange
'drive a wedge between' is the definition.
I can't tell whether this definition defines the answer.
'established area of grass' is the wordplay.
I cannot really understand how this works, but
'established' could be 'est' (abbreviated used in shop signs) and 'est' is found in the answer.
'area' could be 'range' (range is a kind of area) and 'range' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for estrange that I've seen before include "Lose friendship" , "Alienate from friendship" , "Alienate -- sergeant (anag)" , "Drive away" , "Arouse hostility" .)