Onionlike vegetables (5)
I believe the answer is:
leeks
'onionlike vegetables' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for leeks that I've seen before include "Vegetables, emblem of Wales" , "Emblems of 19" , "Vichyssoise ingredient" , "Scallions" , "Welsh vegetables?" .)