Vegetable emblem of Wales (4)
I believe the answer is:
leek
'vegetable emblem of wales' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for leek that I've seen before include "Plant (onion relative) eaten as a vegetable" , "Vegetable related to onions" , "One of the veggies" , "Welsh national symbol" , "Staffordshire town?" .)