Worrier with trouble getting grass (7)
I believe the answer is:
fusspot
'worrier' is the definition.
('fusspot' can be a synonym of 'worrier')
'trouble getting grass' is the wordplay.
'trouble' becomes 'fuss' ('fuss' can be a synonym of 'trouble'**).
'getting' means one lot of letters go next to another.
'grass' becomes 'pot' (cannabis).
'fuss'+'pot'='FUSSPOT'
'with' is the link.
(Other definitions for fusspot that I've seen before include "Nervously agitating type" , "Hard-to-please person" , "One who worries too much" , "song-and-dance man?" , "bit of a worrier" .)