Possible Clues:

• Market heads?
• 'Of shoes and ships and sealing wax, Of . . . . . . . . and kings
• The taxi gets old and vegetates around the capital of Belgium
• Of shoes and ships and ceiling wax,/ of . . . . . . . . and kings (Through the Looking Glass)
• 'Of shoes and ships and sealing wax, of . . . . . . . . and kings'
• '... of -- and kings'
• Begs a cab to get vegetables
• Kale and kohlrabi
• Pop group starts to get extra stroppy after cold vegetables
• Seem to be times for greens