Crowd in garden on either side of road (5)
I believe the answer is:
horde
'crowd' is the definition.
(horde is a kind of crowd)
'garden on either side of road' is the wordplay.
'garden' becomes 'hoe' (I've seen this in other clues).
'on either side of' is an insertion indicator.
'road' becomes 'rd' (abbreviation).
'hoe' enclosing 'rd' is 'HORDE'.
'in' acts as a link.
(Other definitions for horde that I've seen before include "lots of people" , "Large crowd" , "Great crowd" , "Large force" , "Vast multitude" .)