Rubbish in front of elm and two other trees (7)
I believe the answer is:
eyewash
'rubbish' is the definition.
(both can mean nonsense)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for eyewash that I've seen before include "Nonsense (informal)" , "this is soothing sight" , "Pupils may benefit from this" , "Rhubarb" , "Insincere talk or optical lotion" .)