[Arid_gardener] RE: Totem Pole Cactus

[Christine M. Bahto]

ORIGINAL QUESTION:
Date: Wed, 28 Feb 2007 14:32:59 -0700 (MST)
From: vicgelati at hotmail.com

Vicky
85255


We have several 4-foot tall Totem Pole Cacti (lophocereus schottii forma
monstrosus) in our back yard that have been very healthy since they were
planted 2 years ago.  In the last week we noticed that two of the Totem
Poles have turned black at the base of their "trunks" -- this is the section
just above the soil level.  The remaining parts of these two cacti look
fine.

Do you know what could be causing the base to turn black?  What can we do to
solve the problem and ensure the health of these Totem Poles?

Thanks so much for your advice -- we really appreciate it.

ANSWER:
Vicky,

Did you excavate some dirt from around the base of the 2 affected Totem
Poles to see if the area underground is also black?
Is the black area softer than the green healthy areas? Are the plants on
irrigation, if so are they irrigated all year long?

The black areas (if they are soft) are most likely rot. This could be due to
irrigation issues or the plants may not have been healthy when you purchased
them. Cacti need to be kept dry from late October to early March, only
allowing rainfall to water them during those months. Keeping them too wet
will cause them to rot.

You can cut off the healthy parts, about an inch or two above the black
areas and root the pieces. Make sure to use a clean saw to make the cuts and
sterilize the saw with a water/(rubbing) alcohol mixture between cuts. Allow
the wounds to heal for about a week before replanting and do not replant in
the same place where the original plant was, as the bacteria that causes rot
may still be present in the soil. Never put cactus on drip irrigation, only
suppliment with water when we are going through a long period of no rain
(during summer-only). Totem Poles re-root quickly, so water them once every
2 weeks for the first 2 months then reduce watering to every 3 weeks to get
them through the first summer.

Hope this helps,
Christine Bahto
Master Gardener, Maricopa County, U of A Cooperative Extension