Bougainvillea - Trunk Treatment Help

[Absolute]

Earlier this year, I stumbled across a large, discarded Bougainvillea branch. I propagated several hardwood cuttings, most of which rooted. During the earlier stages of growth, a black mold and or fungus outbreak occurred while they were still covered (I believe I left the soil too wet). I treated with a hydrogen peroxide solution and cut away a lot of damaged leaves. Fast-forward and they continued to thrive, so I thought that I had beat this ailment. I transplanted about 8 trees into new pots and they have been growing vigorously since. However, I noticed today that each plant (some more than others) appears to have developed some type of debilitating ailment on the base of the trunk.

Can anyone help me identify this issue? How serious is this problem, and how should I treat it? Am I just over-watering these plants? I really hope to not lose these trees.

 

[SWfloirda]

I've had cuttings of other types of trees take on the appearance as if they are wicking up the water. My theory is that since there is no established stump or nebari that is where the tree is getting it's water from so it is damp there. I did back off of the water until they dried a little more but I think they will be fine.

 

[Absolute]

I appreciate your input, and I certainly hope that's what's going on here. However, the more I look at this the more I think something unwanted is growing on these tree trunks:

 

[Forsoothe!]

That looks like dead moss left-over after a tree has been in constantly wet media, and now the moss has gone dormant or dead. The white upper edges look like mineral deposits, part of the same process. Has this been recently repotted to this drier media? It should brush off with a toothbrush.

 

[Perrywinkle]

My bougainvillea had a similar film of algae growing at the base. I just scrubbed it off with a toothbrush and a small knife. I recommend doing so because it seems to cause the soft wood to rot prematurely if left on.

 

[Absolute]

Thanks for the input. It does seem to be some type of algae or moss growing. I have been working to remove with a brush. It seems to have come back on one trunk - perhaps it wasn't completely removed and it's been very wet this week. Tough to remove below the soil line. Trying to be sensitive to how recently these were rooted. Will continue to combat as best I can - thanks everyone.