Should I remove the limb of a cactus that has a brown spot?


I have a Blue Myrtle Cactus that is overall doing well. It is an indoor cactus. Over the past 3-4 weeks it has developed a brown spot at the end of one of its limbs where there had been some new growth. All the other limbs look great. I do not believe it has been over watered. I wonder if you think it might heal off this area or if I should remove the limb?


Jonathan Foster, Special Projects Assistant

After doing some research on the question, it would seem there are fewer university-backed sources for cactus care than I would prefer. However, I did find a bit of information and, while I haven’t grown a lot of cactus myself, I have a good bit of experience with other succulents. Plus, cacti can be pruned for a variety of reasons (see here and here), so that’s what I’m going to suggest.

My advice is to prune off the entire stem segment where it emerges from the primary stem. There is obviously necrotic (dead) tissue at that tip and I worry about it being a likely spot for secondary infection to occur, so it’s best to remove it. In succulents, I usually strive for the smallest cross section of cut that I can manage, so I don’t think you should cut it near the tip. Take it off at the base with a sharp, clean cut (sanitize your tool first), and then leave it alone. It should callus over in a short period of time, and you have plenty of other segments so I don’t think it will negatively impact the appearance.