Onionlike plant (4)
I believe the answer is:
leek
'onionlike plant' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for leek that I've seen before include "Welsh national emblem" , "One of the veggies" , "Green and white vegetable" , "Welsh symbolic vegetable" , "Eat the vegetable and keel over" .)