This area may be a far cry from the great Old Forest east of the Shire, yet there are willows here, and a small stream nearby. In the first volume of The Lord of the Rings, Frodo and his companions entered the Old Forest to escape the Black Riders. There Old Man Willow trapped them in his branches and nearly drowned them with his sleeping spell before the merry Tom Bombadil rescued them.
Tom sprang away, and breaking off a hanging branch smote the side of the willow with it. ‘You let them out again, Old Man Willow!’ he said. ‘What be you a-thinking of? You should not be waking! Eat earth! Dig deep! Drink water! Go to sleep! Bombadil is talking!’ He then seized Merry’s feet and drew him out of the suddenly widening crack. --“The Old Forest,” The Fellowship of the Ring, by J.R.R. Tolkien
2022 Update: I've temporarily moved the cache until they are done with the new path and landscaping. It's now a bison tube located north of the tree stumps. A little bushwhacking may be required. The hint has been changed.