sick trichocereus

[U365732]

Hi everyone! I'm new to this forum, and am a bit desperate for guidance due to a sick trichocereus cactus.

The cactus was planted in Oct 2015; by mid-February, I observed some shriveled skin and slight narrowing of the ribs (maybe suggesting transplant stress?). At that time I also noted a small area of yellow near the base of the largest spear (5 spears total) and a small hole 6-8 inches up from the ground, in the side of one of the ribs of the large spear. I received pictures of the cactus yesterday (I work from Michigan, "play" in Arizona) and the yellowness has SIGNIFICANTLY increased, now including brown patches - see pictures.

sick trichocereus1.jpg (62.84 KiB) Viewed 694 times

sick trichocereus2.jpg (65.95 KiB) Viewed 694 times

I'm thinking that the root system was not very good when it was planted (the vendor simply put a shovel under the cactus and pulled it out of the ground)....and I let the gardener determine how much water to apply over the winter so not sure about volume....

Has anyone observed this previously?

[esp_imaging]

It could be cold damage. The smaller offsets may be completely OK.
Don't know what Tricho it is, or your climate, or the watering regime over winter, but if it was too cold and/or too wet it may have suffered.

[U365732]

Thanks for the reply!

The vendor calls it "Trichocereus Werdermannianus," but every time I Google that name I get a prompt that suggests that this name is outdated.....

My home is in Maricopa - so ~1 hour south of Phoenix. Good point about the cold - I see that temps did get below freezing (25-28F) for a few days in November/December. Would cold damage now be "growing" up the spears? ....over watering makes sense to me too.

Thank you! All additional thoughts are welcome!!

[esp_imaging]

From http://trichocereus.net/trichocereus-ta ... echinopsis" onclick="window.open(this.href);return false; (assuming T. werdermannianus = T. taquimbalensis, which may not be correct) :

"Frost and Winter protection: Trichocereus taquimbalensis is a typical, cold hardy Trichocereus and can tolerate temperatures down to -5° celsius for very short periods of time. But I would absolutely not recommend keeping it at such low temperatures and it always depends on the general constitution of the plant. Besides, it has to be completely dry and I would recommend to keep it at temps of approximately 10° celius of you overwinter them inside. Wet soil is a killer and should be absolutely avoided."

Basically the cold will kill part of the stem, rot will set in and this will spread.
If you are lucky, it may not completely kill the stem, and scar tissue will form within the stem and limit the spread of rot, although it will be scarred for life.
If you are very unlucky, it will spread to the rest of the offsets and kill the whole plant. If the damaged parts of the stem are hard, not soft and squidgy, I'd think the undamaged offsets will be safe.

[U365732]

esp_imaging - isn't it a bit late for you to be on your computer

Thanks for the information about cold/wet! I'm sending on to my gardener....also trying to find out about how much water was supplied this last winter.

This is good information since her answer is to 'increase the water'....

Please let me know if you think of / find any other information that may help this poor sad cactus