Shredded greens initially given to journalist holding rodent (6)
I believe the answer is:
grated
'shredded' is the definition.
(thesaurus)
'greens initially given to journalist holding rodent' is the wordplay.
'initially' indicates taking the first letters.
'given to' means one lot of letters go next to another.
'journalist' becomes 'ed' (short for editor).
'holding' is an insertion indicator.
'rodent' becomes 'rat' (rat is a kind of rodent).
The initial letter of 'greens' is 'g'.
'g'+'ed'='ged'
'ged' enclosing 'rat' is 'GRATED'.
(Other definitions for grated that I've seen before include "Shredded; was discordant" , "Rubbed harshly as on nerves" , "Made a rasping sound" , "Rasped or scraped" , "Shredded (eg, carrots)" .)