Old Man Willow was a vast, ancient willow by the Withywindle, the river at the heart of the Old Forest east of the Shire.1
Frodo, Sam, Merry and Pippin took the Forest road to avoid the Black Riders, and found that every path bent them down towards the river. Under the great willow a sleepiness took them. Merry and Pippin were caught in cracks that closed in its trunk, and Frodo was pushed into the water; Sam pulled him out. When they lit a fire against the tree it only squeezed tighter, until Tom Bombadil came singing along the bank and ordered it to let them go.1
Eat earth! Dig deep! Drink water! Go to sleep! Bombadil is talking!
That night Tom told the hobbits that the trees of the Old Forest held old grudges against things that walk free upon the earth, and that Old Man Willow was the worst of them: his heart was rotten but his strength was green, and his song and thought ran through the woods along the river.2
He is older than The Lord of the Rings. In Tolkien's poem The Adventures of Tom Bombadil, which first appeared in 1934, the willow catches Tom himself and lets him go when Tom commands it.3
Sources
Citations name the chapter rather than the page, so they work in any edition. The colour of each note shows what kind of source it is.
- Published story The Hobbit and The Lord of the Rings as Tolkien published them.
- Published story The Fellowship of the Ring, Book I, ch. 6, “The Old Forest”
- Published story The Fellowship of the Ring, Book I, ch. 7, “In the House of Tom Bombadil”
- Published story The Adventures of Tom Bombadil (1962), “The Adventures of Tom Bombadil” (first published in the Oxford Magazine, 1934)