Possible Clues:

• A verse often quoted with reason
• Have the same final sound - poetry
• Verse from Frost recital
• That's my her, inversely
• Similarity of sound
• A poet is to know it, in this instance
• What 11-Down doesn't do
• Frost, say, anticipated by a nursery perhaps
• Correspondence in the sounds of two or more words
• ____ or reason