It will work, as long as theres no plant-like chemicals in it. But like Sphagnum moss, it shoult be cut. I got some sphagnum moss that was in strands, making it kind of difficult to feel secure in. But you know what? My blood hates it anyway.
I have a little wooden hide box and a round wooden dish with sphagnum in it, all form fitting. But the snake hates it. It always crawls out of the hidebox when it thinks no ones looking, and burrows in the substrate (repti bark). I always disagreed with newspaper substrate. It looks pretty tacky to begin with, and I can't imagine it being to comfortable to crawl on. If I were you, Id get wooden substrate and use the moss. It might like both. Nice Black too, by the way. I always wondered what an aggressive blood would be like, since there so slow and calm. I also wonder what an aggressive pug would be like.