Possible Clues:

• Aromatic herb used as seasoning
• Herb used with potatoes
• Pickle preference
• Type of herby weed will be missing raw edge behind drive
• Pickle flavouring making duke sick
• Herb for gravadlax
• Lecturer to top up pickle ingredient
• Flavoring herb
• Plant copied down as part of intersecting answer
• Plant 9, first reduced by 50%, finally by 90%