We Get Questions – 2 or 3 in One!


A neighbor gave me some cuttings from a couple of their cactus plants. Can you help me ID? I have an idea on the cactus on the right side, but for the sake of not sounding stupid ill defer to your expertise. The one on the left I can’t don’t have a clue. Your help is greatly appreciated.

I also have a Ferocactus with what looks to be some black fungus or mold or bug in the deep ridges, new growth and on the white hairy areoles. I don’t have a picture at this time, but can provide one if necessary. The cactus is firm and very healthy otherwise. I have been hitting it with Neem weekly which seems to be working fine. The black stuff can be easily wiped away with a paper towel and/or soft brush. I was also considering repotting it but have not done so thinking that winter time is not the best time to do so?

Any input you have is of course appreciated.



The smaller left hand cut, looks like it is a type of Cylindropuntia fulgida, most likely the variety Cylindropuntia fulgida mammillata. The larger one is Cereus peruviana monstrose. On your Ferocactus, I would not repot until late March-April, cactus are dormant over the winter so they don’t like root disturbance and it can lead to infection in cool wet weather. If you have treated a few times with Neem I would just take a soft small artist brush and clean the skin with warm soapy water and let it dry out. Hopefully it is just sooty-mold and will clean right off.

Good luck,


Thanks a TON! I thought the one was a Cereus Monstrose for sure, but the Cylindropuntia has been difficult to ID. That’s part of the fun I know.

My Ferocactus is soooo cool. I’ll send a photo some time. The black stuff seems pretty harmless, and ill get it cleaned up and replanted early spring.

Thanks again


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