Question
Dr. Steve,

My 9 year old rose of sharon tree has blue green moss like areas on the entire trunk and the bark is now spliting at the ground level.I have  wrapped the trunk with tree wrap and now the wrap has torn at the site of the splitting and the split appears to be getting larger.  I sprayed a tree paint into the split areas hoping this would seal the splits.  My local garden shop also sold me a liquid solution to mix with water and pour around the tree which is to help with fungus.  Nothing is working.  What do I do?

Answer
Hi Sharon:
This growth may be lichens.  These are "leaf-like" gray green growths.  These and our garden variety moss are not considered disease organisms. Lichens are commonly seen growing on older or declining plants and on plants that are in the shade.  They can grow on rocks and fences posts too.  They are more the result of decline rather than the cause. The bark split was probably caused from something else, maybe internal decay, injury, or weather related- difficult to say.  Tree wraps are of limited use. Probably best to leave the area open since the wraps can harbor insects. Tree paints are also of limited value, some even worse than nothing on the area.

Regards
Steve