Just heard this song performed by Maura O'Connell & friends- truly a treasure- beautifully written & sung. I believe the title is a reference to the Virgin Mary. In Catholicism she is associated with the color blue. She is often depicted in Middle Ages and Renaissance art in blue dress. The rose is a symbol of the feminine. The allusions to the story & message of Jesus Christ are obvious, as are the ideas of transformation & self-discovery. My guess is there's a lot of autobiographical stuff in there as well. I love how the song evokes both the past & present & stirs deep emotion- at least it does for me. Many thanks to the composer - beautiful song.