Squeeze garden into trimmed surroundings (8)
I believe the answer is:
shoehorn
'squeeze' is the definition.
(both can mean to force something in)
'garden into trimmed surroundings' is the wordplay.
'garden' becomes 'hoe' (to garden could mean to hoe).
'into' means one lot of letters goes inside another.
'trimmed surroundings' becomes 'shorn' (I can't explain this - if you can you should give a lot more credence to this answer).
'hoe' put into 'shorn' is 'SHOEHORN'.
(Other definitions for shoehorn that I've seen before include "It facilitates getting foot into footwear" , "to make output of last worker yield more" , "Aid to putting on footwear" , "Aid to squeezing foot into footwear" , "What wife too big for her boots may need" .)