Trim bush (6)
I believe the answer is:
spruce
I believe this is a double definition.
'trim' is the first definition.
(synonyms)
'bush' is the second definition.
(spruce is a type of tree or bush)
(Other definitions for spruce that I've seen before include "One [TYPE OF TREE]" , "Smart and tidy - tree" , "Neat - evergreen" , "Natty as a tree" , "Evergreen pyramid-shaped trees" .)