Question
I have planted 5 Alexandras and they are growing beautifully in red clay soil. One of the trees, now about 10 feet tall, keeps getting covered in black sooty stuff and ants climb all over it. I have tried washing it off but it's very difficult and just returns anyway. Could you please tell mw what to treat it with?

Answer
Hi Louie, it sounds like "Sooty Mold" an innocuous fungus that is attracted to the secretions given off by small insects like Aphids, as they feed, the ants are also attracted to this substance; I would treat the effected fronds with an Insecticidal Soap to eradicate the insects which will in turn eliminate any further Mold developing. The residual Mold will eventually disappear in time, but don't worry about it, for it is harmless, its the insects that need to be addressed. Nick