Perhaps King Edward's dropping round junk (6)
I believe the answer is:
potato
'perhaps king edward's' is the definition.
(King Edward is a type of potato)
'dropping round junk' is the wordplay.
'dropping' becomes 'poo' (informal term for excrement).
'round' is an insertion indicator.
'junk' becomes 'tat' (I've seen this before).
'poo' enclosing 'tat' is 'POTATO'.
(Other definitions for potato that I've seen before include "The staple food is strangely too apt" , "Vegetable with eyes" , "Murphy (informal)" , "A plant; hole in sock (colloq.)" , "Common vegetable" .)