Scheme for part of garden (4)
I believe the answer is:
plot
I believe this clue is a triple definition!
'scheme' is the first definition.
(I know that plot is a is a more specific form of the action of scheme)
'for part' is the second definition.
(I have seen 'part of garden' mean 'plot' so perhaps 'part' could also mean 'plot')
'of' is a link.
'garden' is the third definition.
(I've seen this before)
(Other definitions for plot that I've seen before include "Make map" , "Chart - area" , "Draw (graph)" , "Small area of ground" , "Story or piece of land" .)