Is New Zealand Sphagnum Moss or American Sphagnum Moss a good or bad addition to bonsai soil for Yamadori collection in the Spring or for trees that have week roots discovered during repotting?
I have found it useful as a top dressing to prevent dehydration of the surface soil in free draining mixes when working with newly collected trees. I feel this is an important detail for newly collected yamadori.
I do not mix in with the soil so cannot comment on that. I prefer the New Zealand white sphagnum moss for this purpose and shred it on the coarse seive of my soil screening set.
I must admit to a bias for inorganic mixes in my climate and for the species i work with.