Genie, Glen sang this at our Seattle song circle. There's a nice recording of it on Seamus Kennedy's CD "A Smile and a Tear" http://www.cdbaby.com/cd/seamuskennedy10
This is from the CD liner notes: "This poem, written by Joseph Plunkett in 1911, was handed to Grace Gifford Plunkett, his new bride on the morning of May 4th 1916, just before he walked out to face the firing-squad." "Joseph Plunkett was 19 yrs old when he left his sick bed (he suffered from TB) to fight alongside Padraig Pearse and the other freedom fighters in the Easter Rebellion in Dublin, 1916. The Uprising was quelled and many of the rebels were executed by the English. At 1:30 a.m. on the 4th of May, Joseph Plunkett was led handcuffed into the chapel of Kilmainham Jail, where Father Eugene McCarthy united him in matrimony with his fiancee Grace Gifford. They were separated immediately after the ceremony. Just before dawn, Grace was brought back to his cell and they were allowed ten minutes together, and then as she left Joseph gave her the words of a poem he had written in 1911 - I See His Blood Upon the Rose. At dawn, his life was ended by an English firing-squad in Stonebreakers's yard." By the way, it's a great CD - I recommend it highly.
Cheers, S. in Seattle