Question

Sad cactus   QUESTION: Hi Maureen, I found your note to the lady who had an indoor cactus, helpful, but have a slightly different problem. We have an outdoor Pilosocereus Azureus in a pot. It is about 16". We live in So.Calif. and it got alot of rain recently. It now has black rot (soft spot) midway on the plant and in two places on the top. The pot is glazed ceramic. Shall we "surgically remove the rot, or?? It is lost? We are standing by..hoping for a quick response. Thank you so much. Lesanne

ANSWER: Dear Lesanne,

It's hard to tell how extensive that rot is but it is worrisome that there is a color change above the rot which I'm guessing goes all the way up?  You can try a couple of things. 1.) with a very sharp, serialized (w/etoh) knife see if you can cut out the rot and still have it be able to stand.  You need to resterialize with each cut and you have to get to totally clean tissue - greenish-white - no discoloration at all.  You need to go slowly.  Depending on how wide the plant is you may be able to get to clean tissue.  Then brush with fungicide, put in the shade and don't water it for awhile.   If you are able to to that by all means do the same for the small areas at the top that are rotted. I suspect,tho, that the rot is throughout that whole section. I just can' tell you that for sure.

2.) If the rot is too deep your other alternative is to cut that entire piece off starting a couple of inches below where you can see it.  Then you have to continue to cut till you get to clean tissue again (sterilize knife each time).  Tho rot usually develops from the roots up there are times when there is a small cut, bruise etc. on the plant that you may not even notice that allows for entry of pathogens.  The rot may have started before your rains but the rain was excessive and encouraged it's growth.  That looks like what happened to your plant. If you have to cut he top off and want to keep the remaining plant (they will branch, but slowly) you have to brush that clean cut with fungicide and let it callous.  When it does, I'd put it in a smaller pot that keeps it stable but not roomy (terra cotta) with well draining cactus medium.  Don't water it for at least a week after repotting and be sure to look at the roots to see that they are healthy (nice, fat, white) cause if they look yucky I don' think you can save the plant at all and you needn't go to all that trouble.

In the smaller pot it will branch more quickly and they actually can conceal the cut in time, or, you can cut the branch off and start a whole new plant. I love this cactus but it likes hot, dry, sunny.  If it's looking to be rainy for awhile you need to bring it in and then gradually back out to the sun. Cactus go through a dormancy period as well when they don't want any water and need to be kept cool.  In habitat it's usually dormant from Oct. to March or so. Here in the Northeast I keep my cacti in an unheated but not freezing room during those months gradually withholding water in Sept., stopping completely in Oct. and gradually starting again in March. Then they get to go out and HAVE FUN!  I hate it but they do much better and get terrific blooms all summer.  It doesn't take much to keep those of us in 10 feet of snow land happy.

You need to think about your climate and see what you want to do.  If not complete dormancy I would at least drastically cut back on water during winter.  The dormancy is also caused by change in daylight time and any temp decrease.

Anyway, sorry to go on.  Bottom line is try it (that's my vote anyway). If you don't it will die for sure as the rot spreads down to the roots.

If I can help you any further let me know and courage!

Maureen

---------- FOLLOW-UP ----------

QUESTION: Hi Maureen, I just talked about you yesterday! We watered the two halves for the first time. Both parts look fine..no further decay. We moved both parts back into the sun. I said, as soon as we see signs of any growth, I am going to write to Maureen and let her know that all is well. So far..the tall top part, looks the same, minus top. The old root piece, that was repotted (roots were fine) looks a little less vibrant..it's top callous looks a bit dried out. Thanks for checking. And thanks again, for you help..looks like it meant a difference to this handsome cactus. Lesanne

Answer
Dear Lesanne,

Be careful of the sun.  You need to get them used to it gradually or they will burn.  The callous on the old plant should look dried out, no worries.  Sounds like you did agood job and let me know when yo get new growth - careful watering till then.

Yea!
Maureen