Hi there!

I bought this cactus about a year ago from a neat little nursery in the mountains of NC. I was told that it is called a "Christmas Tree Cactus", but I dont think that is what it actually is! I searched around quite a bit and have not had a lot of luck. Even the plant scanner app came up short. Any ideas out there?

FYI - This cactus was about 6 inches tall when I bought it... In just over a year it is now 26" tall and sprawling... I was interested in knowing the name because it has begun slumping over and it very unpredictable with its water needs... Didn't know if it needs repotted or what to do to keep it going strong.

Thanks so much!

Opuntia monacantha monstrose.
Not a TRUE monstrose plant, but infected with a Phytoplasma infection.



It looks to be in a large enough pot. No need to repot it.

Thank you! What would you recommend to solve the infection and keep it healthy moving forward?

Truth is that there's no easy way. Most people just keep their plants with the infection, and treat it as a normal plant. The phytoplasma infection only makes the plant pup more. Nurseries sell these plants, as a novelty. If you like it the way it is, keep it that way. I've heard some pretty absurd ways to fix the infection, which I would not try.

It does look to be stretching out. If you can manage it, more light would help the slumping over.

@Hlutzow
The stretching is somewhat normal for a plant with this kind of infection. It would help to know the growing conditions to tell if this is actually etiolation, or just the infection. Even if grown in full sun, infected plants tend to grow stretched pads.

The cactus would benefit from stronger light, though judging by the current location right by a big window, I don't know if that's possible for now.

Aeonium2003 said:@Hlutzow
The stretching is somewhat normal for a plant with this kind of infection. It would help to know the growing conditions to tell if this is actually etiolation, or just the infection. Even if grown in full sun, infected plants tend to grow stretched pads.

I agree that this cactus tends to grow long pads that would look like etiolation on any other cactus. But. I have grown this cactus and the narrowing in the middle of a pad only happen when it isn't getting enough light. It makes it look like taffy being pulled. It's a neat effect, but it makes it difficult for the plant to stand on its own and it tends to flop over.

OOps. Didn't see that until you pointed it out.

Aeonium2003 said:Opuntia monacantha monstrose.
Not a TRUE monstrose plant, but infected with a Phytoplasma infection.

Phytoplasma is an infection that does cause the montrose look. It is a true monstrose. It doesn't matter what causes the mutation but, in this case, its permanent and naturally occurring. It is a true monstrose.

From OrchidBob: The precise cause of these mutations is unknown. Many suppose a bacterial, fungal or viral infection may cause some genetic disturbance. Another pathogen called a phytoplasma (sort of half way between a bacteria and a virus) has been shown to be the causative agent of cresting in at least some species. Chemical and physical trauma have to be included in the list of possibilities, though usually that sort of occurence damages the meristem (growth center) in such a way that it simply begins to divide, resulting in 'ordinary' branching or multiple heads. But for some reason, sometimes the result is crestation instead. I am sure pesticides and other toxic chemicals can alter gene function and result in mutations like this as well. Perhaps radiation from the sun is another possible mutation cause. Some plants seem more prone to this mutation at various seasons, so temperature, humidity or heat may have some influence. Some nutritional deficiencies have been known to lead to cresting mutations (e.g., Zinc deficiency) as well. And sometimes mutations can occur spontaneously (no external force needed)- just a chromosomal aberration resulting from some internal error in transcription or translation.

Here is the link:
https://davesgarden.com/guides...

@DaisyI
Unfortunately, the facts are the facts. A phytoplasma infection is also known as Witches broom. I think (respectfully) that you need to read more about mutants in cacti.
https://www.sublimesucculents....

True monstose plants have had damage to their apical meristem. This is not the case with Witches broom, or phytoplasma.

Also see this video. At the time 9:37, he explains witches broom. https://www.youtube.com/watch?...

"By the way, there is also something called witch's broom, also known as a phytoplasma infection.
You can see an example of it on the screen now.
It may look a bit like a mutant plant to the untrained eye, but it is not.
As you may have guessed from the word "infection", this is not a good thing.
Not a good thing at all.
In fact, if you see a plant with this kind of growth pattern in a plant nursery, runaway!
Do not buy the plant, it is NOT a monstrose. It is a sick plant that may eventually die and can contaminate really quick your plant
collection. We've seen earlier examples of a multi-branch freak, but what you can see here is different:
the branches never get to grow tall, they keep pupping and pupping and pupping, and
the plant may die unless you act.
Witch's broom is spread by the insect that you can see now, the cochineal, also known
as mealybug.
It is a parent of the scale insect.
Mealybugs are one of the most dreaded pests on the san pedro."

No credits, not even an author.

Not sure what you mean. I got that quote from the video I linked.

Hm, I need to revisit my understanding of monstrose cacti then, I always think it is the definition for the cactus that grow crazy wild and ended up into a crested cacti.
I assume the above opuntia is a healthy happy plant who like its new environment, and grew a lot of new leaves and pads ?

I'll post my opuntia in the c&c chat for a simple chat, not to scare @MrZenInNC in his thread that just need an ID

Hi here is my troubled cactus, can you I D it for me?

Hi here is my troubled cactus, can you I D it for me?

Looks like a form of this species

Papery Spine Cactus (Tephrocactus articulatus)