|The trunk of my Bottlebrush tree seem to be|
|If your bottlebrush is producing new growth and looks otherwise healthy, I don't think the bark splitting is anything to worry about. The bark tends to produce fissures as it ages, especially on the side that receive winter sunshine. The bark then dries out and looks shaggy, but the wood is sound. I don't think splintering bark should cause concern.
Best wishes with your bottlebrush!