Expert: Jeff - 10/7/2002

Question
We have a 50+ year old cactus that is dying fast.  Its about 3ft tall, has arms with 3 edges ,each arm is about 2 inches wide.  About a week ago we notice over half the plant was turning brown/black.  It started at the roots and worked its way up fast.  The top is still nice and green.  We changed the soil but no good.  Still dying.  I have pictures of this.  Could you offer any advice?  Thanks.  

Answer
Dear Brent,

Yes, you can save the plant, though it certainly won't be what it was; however, it should grow back.

Using a knife, cut out all of the rot, and making the last cut into healthy tissue with a sterile knife, set aside the healthy pieces, powdering the cut ends of the healthy pieces with flowers of sulphur (sulphur powder). They'll root best when there's plenty of sun and the temp is 70F or above, so you may have to wait until spring, but that's not a problem with these plants; they'll wait, too. Putting the cut ends onto a thinnish layer of soil in a pot - remember, you're just trying to get it to root. Anyway, place the cut end on or slightly in the soil, surround it with top dressing to support it, and put it in a dry, warm, sunlit place. Don't water, mist every few days, and in the Spring or before it should have rooted.

I don't have an explanation for the rot - I've had cactus do the same thing. It's some sort of fungal infection.

Hope this helps.

Kind regards,

Jeff