We just bought a place in Mesa AZ and have two organ cactus plants in an East facing area. I have noticed that the columns are turning to wood at the bottom, but is still green on top. What is causing this and is there anything I can do to help them. Since we didn’t plant these cactus I am not sure what care was taken when they were planted and for how long they have been here.
Probably just "corking", a natural aging phenomenon.
From the photo, with the plant on the right, it appears excessive, but doesn't look like a fungus to me. Even if it is, there is not much you can do except adjust the watering to an appropriate amount, and avoid sprinklers hitting on the stems.
By the way, there appears to be two different types planted next to each other, maybe two species of the genus Stenocereus. I'm not a cacti expert even though I grew up in Scottsdale with a horticulturist father who was on the board of the Desert Botanical Garden. If you want to get into it, you can visit that great resource or use the online cactiguide.com
Can you plant upper part of broken organ cactus like others and start a new plant?
Most cactus plants can be started from a piece of the plant. Be sure that the broken part is cut clean with a razor cutter then follow the instructions in this article to help you turn your start into a new plant:
I have one of these approx 18” high which has become very narrow at base. I would like to repot into a larger pot and submerge the narrow part of the base into the soil approx 4”. I am concerned the plant may not accept this or am I just better off leaving it and supporting it with a stake ?
I think it would be fine to repot the cactus in just one size larger than the pot it's in, and if it's not overwatered, burying the base a bit shouldn't hurt it. However, you may want to consider, instead, pruning it a bit. Don't do both - the cactus may not deal well with that much change - just a thought.
Here are two articles to help:
I have been offered 2 Organ Pipe cacti (each about 8-10' with multiple limbs) and a 6-7' tall Totem, as the owner doesn't want them anymore, plus he wants to give the Boojum/Cirio tree (within 2 feet of the Organ Pipes and Totem) more room to grow. (He's had the Boojum for almost 45 years. Now over 15' tall, It was a 3" high gift in 1975.) My concern is how to best remove the 3 large cacti from around the Boojum without damaging the Boojum (I believe the cacti will be more resilient). I cannot find any information about their root structure online. Any suggestions are welcome, and thank you!
I did find a reference that said Boojum was easily dug and transplanted so it must not have a very extensive root system. But this one is very tall and old and you sure don't want to injure it. I would say it was a job for an arborist.
I am leaving sections of organ pipe cuttings dry to propagate. It’s been almost 2 weeks and I’ve read where I can take up to two months to properly dry. What’s happening now though is that there are a few sections on the ribs that are training weight and shrinking a little bit, like it’s drying out. Does that mean it’s ready to put in the planting medium? Or a sign of some infection? What should I do? Thanks advance!!
This does appear to be an infection. Most times, this happens from using improperly sanitized pruners. From here, I would dust with a fungicide. Wettable sulfur is my go to for application like this. Unfortunately, I can't see the cut end, so I can't see whether it has calloused, or not. Once the happens, it will be time to plant.
Here is an article that will help you with fungicide use:
This collection of articles will help you with the care of the cactus:
What's the closest I can plant an Arizona Organ Pipe cactus near a house? The main concern is future root growth. Also, does pruning stems headed toward house effect root growth underneath?
Considering it can attain the size of a small tree, it's best to plant it at least 15 feet from a structure.
I have a 4ft organ pipe, cactus arm that I just cut off from the main plant. However, I think even 4 feet is much too large for transport. I was wondering if it’s OK to just cut the top off of the organ pipe, cactus arm (maybe a foot) and then follow the steps to allow for it to callus and then plant. I know it will be small, but at least then I can travel with it
If you can get an entire offset without cutting (That is, that you can get a true, full offset by pulling off a segment, completely), then that would be a much better option. It will take much less time to root and callus, that way. Otherwise, here are some articles that will help: