Weed crushed under logs (9)
I believe the answer is:
groundsel
'weed' is the definition.
(groundsel is a kind of weed)
'crushed under logs' is the wordplay.
'crushed' indicates an anagram.
'under'+'logs'='underlogs'
'underlogs' is an anagram of 'GROUNDSEL'.
(Other definitions for groundsel that I've seen before include "Plant of daisy family" , "plant, unwanted?" , "feed to the birds" , "Common weed" .)