Possible Clues:

• Root vegetable
• Edible root, eaten cooked — fils, say (anag)
• A fly is buzzing around small edible plant
• Black root vegetable
• A fly is whirling under small vegetable
• Brief hippy movement's condition, close to assembly plant
• Oyster plant
• ... Sarah's condition initially yields
• Purple-flowered oyster-plant
• Existence