How grass cutter's cut line of bushes (8)
I believe the answer is:
hedgerow
'line of bushes' is the definition.
(I've seen this before)
'how grass cutter's cut' is the wordplay.
'grass cutter' becomes 'edger' (type of trimmer).
'cut' indicates putting letters inside (some letters have cut into others).
'how' placed around 'edger' is 'HEDGEROW'.
(Other definitions for hedgerow that I've seen before include "Line of entwined bushes and trees" , "Line of shrubs as barrier" , "natural fence" , "Field border" , "Greenery between fields" .)