Possible Clues:

• Potatoes and yams
• Potatoes and dahlias, say
• Potatoes, for instance
• Yams, e.g
• White truffles, for example
• Underground network with pipe to right pole
• Oddly rebuts the potatoes and dahlias
• Rutabagas, e.g.
• Brutes of potatoes
• Potatoes - real brutes