Men overwhelmed by silent support back in garden (9)
I believe the answer is:
arboretum
'garden' is the definition.
(I've seen this before)
'men overwhelmed by silent support back' is the wordplay.
'men' becomes 'or' (I've seen this in other clues).
'overwhelmed by' means one lot of letters goes inside another (I've seen this in other clues).
'silent' becomes 'mute' ('mute' can be a synonym of 'silent').
'support' becomes 'bra' (a support for the breasts**).
'back' says the letters should be written backwards.
'mute'+'bra'='mutebra'
'mutebra' reversed gives 'arbetum'.
'or' placed within 'arbetum' is 'ARBORETUM'.
'in' is the link.
(Other definitions for arboretum that I've seen before include "area with great growth" , "Collection of elders, say" , "Botanical tree garden" , "Tree display centre" , "Place for cultivation of trees" .)