Question
Hi I live in southern Ca. Last year I notice the bark on top of some of my branches was coming off but the branch had a lot!! of new growth. I pulled on it and it broke very easily. It was 3 inches in diameter. The wood at the brake looked rotten.
How I have a lot of mushrooms growing in the dirt around the base of the tree.
Can you help.
Thanks Wayne

Answer
Wayne:
If these mushroom are attached to the base of the tree or to the roots, this is an indication that there is some level of decay inside the tree- probably of the heartwood portion. This is a definite sign of decline.  At this point, there is nothing that will halt or reverse this slow progressive situation.  Removing the mushrooms will not stop this process.  Loss of bark, as you describe, is probably the result of the decline.  Mimosa is susceptible to several fungal organisms that produce these "conks" or basidiocarps near the base.  They can also be a sign of root rot as well.

Mimosa, even though quiet beautiful with aromatic flowers, does have a bad rep as being susceptible to also a wilt disease called Fusarium Wilt.  In my part of the world, this tree is most often seen on old home sites and in rural areas.

I suspect that at some point you will need to consider replacement.  Unfortunately I would not  replace this tree with another mimosa since some of these microorganisms can be present in the soil for extended periods.

Regards
Steve