This one will be pretty familiar, although I think there’s a bit more to it than meets the eye. It’s not as tightly written as the Maiden that is Matchless, but the tripartite division of white (divine purity), blood-red (sacramental blood) and thorn (agony of the cross) has a definite Christian exegetical quality about it, while the accompanying verses are practically a catechism. The final “bark”/”bitter as any gall” verse adds the bitterness of mortality to the list, then hits back with the redemption of souls through Christ’s sacrifice. (I left this verse out, probably wrongly, as it wasn’t in most of the sources I was using.)
As for the arrangement, I worked hard on these harmonies – with a bit of help from friends on Mudcat – and possibly a bit too hard; the effect isn’t quite as satisfactory as on the Boar’s Head Carol. Still, this was my first attempt with self-written harmony (and the Boar’s Head the second); upward and onward!