I Found the Entwives!

[Inziladun]

Originally Posted by Nerwen

I'm inclined to think the creature described by Sam was also merely a troll- but did Tolkien ever clarify that? Anyone know?

In Letters, Tolkien says nothing about the strange creature seen in the Shire. However:

There are or were no Ents in the older stories-because the Ents in fact only presented themselves to my sight, without premeditation or any previous conscious knowledge, when I came to Chapter IV of Book Three.

Letter 247

In HOME I Christopher Tolkien notes that the conversation in the Green Dragon about the Tree-men was present in the original draft, and posits that it could indeed have been a "premonition" of the Ents.

Back in Letters, Tolkien says:

Though I knew for years that Frodo would run into a tree-adventure somewhere far down the Great River, I have no recollection of inventing Ents. I came at last to the point, and wrote the 'Treebeard' chapter without any recollection of any previous thought: just as it is now.

Letter 180

With that, I think I lean to the idea that Tolkien had put the line in the hobbits' talk at the inn to presage the undeveloped adventure with the 'Tree-Men', and then just forgot about it (after all, it did take him a long time and a lot of rewriting to finish the book).