I tried moving this to a perlite/pumice/scoria soil mix to get more water retention, so I didn’t have to keep it in a pot of water. It didn’t work. I’ve put it back in the water. Next year I might try adding some sphagnum moss to the mix.
I’m writing this post up in late March, so I should include some photos of the revived tree, shouldn’t I? Let’s make my lack of diligence work for this post.