I let that native (? I assume) moss grow wherever it likes. It is soft, green, and helps choke out weeds. When it gets nasty looking (brown and dry), it is easy to just pluck up by the chunks, or rake through to break it up. I'm also becoming more tolerant of the dratted invasive buttercup (Ranunculus repens), often enjoying their cheery bloom comingled with my 'real' plants. Choose battles wisely.
