Hello, I have had this cactus for 43 years, and it has grown steadily and beautifully. Suddenly, the highest "branch" of it has a white "cap" on it. In the photo, it looks like brown scarring, but it is NOT that. It's definitely white. Can you tell what it is from the attached photo? Is there anything I can do to treat it? Any advice will be greatly appreciated as this is my very favorite plant. Thanks!
That was unusual ... So the tip was not damaged? It just collapsed and turned white? And the usual questions: 1. Is it soft? 2. Does it spread?
Thank you for responding. The tip was not damaged. Other than turning the plant, it has not been moved. The tip doesn't feel soft, but when I touched it to see, tiny flakes of the white stuff floated into the air. I hope I didn't start a more rapid spreading of whatever this is. The tip isn't profoundly collapsed, and there is no evidence of other spires of the plant being involved.
Have you checked the bottom of the container/the root ball of the plant in awhile? It may need some root help. :)
The cactus has been in the same pot for about 10 years. Originally, the pot was too large and the plant didn't grow much, but in the past 5 years, it's doubled in size. What type of root help are you recommending ~ a new, bigger pot, or something else?
Typical plant maintenance. If it has been in the pot that long it wouldn't surprise me that it has a bit of top damage. I'd take it outside and carefully tip it over and remove the pot. Check if the roots have fully formed the pot (it needs a bigger pot at this point or a root trim using a clean blade/etc.) or if there is any other kind of pests/damage/etc. Re-pot into a bigger pot after breaking up the root-ball somewhat and providing fresh dirt/organic matter/compost/etc, water. If it doesn't need a bigger pot, simply clean the other out, provide fresh material and replant. That is what I would do anyway; this may or may not be exactly 100% accurate as I am not a professional but you can at least check the roots without much fear of damage. (And if the pots are plastic, well lets just say I prefer clay/ceramic/non-plastic/glass. Anything but plastic! ) :)
Thank you. Will try re-potting. I only use clay pots. A local plant store owner told me to cut off the part with the white on it, saying the rot would spread downward. I did this, cutting about an inch below the white part. I hope this wasn't a mistake.
The pot does indeed look small, the roots of columnar cacti usually grow fast. I cannot say if that caused the death of that tip, lack of space typically does not harm the cactus, it just makes grow more slowly. A thought: Is the plant so tall that the sunlight no longer reached the damaged part?
