Black on BRT lower trunk/Nebari

Hello all. Any feedback appreciated. What’s the black substance on my BRT? Mold of some sort? The tree is very healthy and has thrived outdoors this summer. I did notice it when indoors during Winter (Chicago Zone 5b). I thought the sun may help in removing it. Lastly, from an aesthetics standpoint, is there a product I can use, or make myself to remove it? Big thanks…

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What is a BRT? Bacon, Radish, and Tomato comes to mind, but that is a different type of website. Sorry for the sarcasm, but knowing the type of tree is probably important. I try to list both the common and scientific name at some point early in the post along with any shorthand I am going to use.


I believe it stands for “Brazilian Rain Tree.”

correct. sorry. didn’t realize…

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I have no experience with Brazilian Rain Tree (Pithecellobium tortum). Will the black stuff brush off with a tooth brush or similar instrument. In that case it might be a moss or similar growing on the bark. If it is a moss or similar, spraying with vinegar can discourage/kill it. if it is some sort of deeper fungal or bacterial problem I can not offer any real help.

Much thanks Marty…

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How did you make out with your black gunk?

I have a Texas Ebony with a similar but less severe situation. To me it looks like a mold or algae, but it also looks like it causes the bark to peel, so i’ve hesitated scrubbing it off lest i do more damage and invite pathogens into the tree.

If i were to go at it with a toothbrush, is there a solution i can use to “disinfect”?


Hello Jim, I never addressed it — job related around COVID…just now get settled. A

…as I was saying, never got to tackle it. Anyway, it has been inside and I’m going to see what I can do. Apologize I don’t have answer for you, but life got in the way. I’ll definitely let you know. By the way, the bark coming off is a trait of a Brazilian raintree (Pithecellobium tortum) and was related to other issue. I’ll be back in touch…

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…wasn’t related to other issue…

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