Why did this cactus rot?
A month ago I wrote a post about one of my favorite succulent container combinations: Silver Torch cacti (Cleistocactus straussii) and Agave schidigera 'Shira ito no Ohi'. In addition to the Silver Torch cacti planted in that pot, I had two others in a separate terracotta pot. They had grown just as much and I had plans to transfer them to a larger container this spring.
Like all my cacti, they were protected from the winter rains (not like it’s been a wet winter anyway). Much to my surprise, I noticed yesterday that the tallest of these two Silver Torch cacti had flopped over due to rot toward the bottom of the stem, an inch or so above soil level.
The soil is bone dry and I have no explanation what might have happened here. Sure, it’s possible that a stray rain drop or two might have landed on it during a rain storm, but if it’s that sensitive to moisture, wouldn’t it have rotted at the soil level?
On Friday afternoon I decided to do a radical amputation to save the patient’s life. Out came a sharp fillet knife, and in a split second I had cut off the rotten parts. I then dunked the cut surface in 70% isopropyl alcohol to seal it…
…and I drizzled some alcohol on the cut off section still in the pot. I’m hoping it will heal so the pup originating from the rotten stem will survive.
I placed the cut segment in a dry and shady spot where I will let it callus over for a month before planting it in a new container.
With temperatures warming up, I have every hope that it will survive and eventually become as healthy as the ones in the other pot:
|Silver Torch cacti (Cleistocactus straussii) and |
Agave schidigera 'Shira ito no Ohi'