Possible Clues:

• Vegetable sounding like a pea?
• National emblem featuring in disclosure, reportedly
• Shelter King, a favourite of the Welsh
• Soup bulb
• National emblem in shelter above king
• Vegetable, an emblem of Wales
• One of the two vegetables used to make vichyssoise
• Relative of an onion
• Cut head off smooth and glossy vegetable
• Vegetable appearing on the badge of the Welsh Guards