I used to start moss in my Bonsai pots ; however, in some cases , the moss and lichen gets out of hand and has caused root rot. It appears that thick moss and lichen can stop water from running through/ evaporating and whilst feeling dry , the roots are deep down and rotting. It could be that as I have 100 bonsai trees, I don`t get round to trimming and weeding to all pots . Does anyone else have this problem? I have MS , which does not help as I am often too ill to work . But I am very keen on recommending Bonsai keeping as an ideal hobby for people with neurological illnesses.