Let me try to post a clean version with chords. The text came from Shay Black so I'm not making any up! The chords are my own fault. I am omitting the fadas or whatever those little marks are on the Irish words, if someone would like to clean that up please do.

The Willow Tree
by Padraigin ni Uallachain

Em                         Am          D
Down by the river there's a tall willow tree,
    Em                  G       D
Who weeps all night for you and me.
         Em       Am      Em   
And it's lay down low, my love.


Chorus:
         G       D       Am
And it's lay you down, my own true love.
Em          D          Em       D
Shadows are falling and night has come,
         Em       Am      Em
And it's lay down low, my love.



Under the branches of the brown thorn tree,

The wild bird is watching over Lios na Si (pron. Leeshna-She)

And it's lay down low, my love.



On Lake Derravaragh there's a white-feathered swan

Who sings with sorrow the whole night long.

And it's lay down low, my love.



The moon is moving over Poulnabrone (Poll na Bron)

Where two lovers are lying on their bed of stone.

And it's lay down low, my love.


(repeat verse 1 and chorus)