Possible Clues:

• In magazine I read it adds zest to foods
• That's enough to mar joram or gain from it
• With 'It's in the garden, love,' I rang off
• Roaring out �Start off with the herb!�
• Marjoram has one among the pipes
• 'For flavouring, a vital necessity,' I interposed
• Herb, or one on horseback
• Herb sounds as if in the USA
• Where the pipes are calling about one in an aromatic manner
• The alternative to the gain you get from marjoram