I was so focused on telling you the perils of too much sun on succulents last week that I really didn’t talk much about the effects of too much sun on cactus in particular. They, too, can be damaged in heat like we are experiencing now. The sun may be more intense in Muleshoe than at your house since we are about 4,000 feet above sea level, and that altitude difference really does make the sun stronger and harder on the plants. But too much sun is just too much sun, wherever you are.
When I went out in search of burned cactus to share with you, I discovered that I really didn’t have too many cactus that had burned; it was my succulents that suffered the most, so I guess that is why I was so focused on them last week. But this little horse crippler that I had transplanted without regard to the heat suffered some burns on its edges and is now a faded green.
Compare that to this one that has lived in filtered shade all its life.
There are always exceptions to the rule, however, and the one pictured below has always been in full sun. The body is nice and green, but look at the red spines, which may just be the way this one’s spines are colored, but I as I recall they weren’t this red last year, and I think it is due to the sun. Notice the body is nice and green. That is because it, too, has been in full sun all its life during times of less intense heat and has built up a toughened outer layer of cells for protection.
Prickly pear, which in nature is nearly always in full sun, as this specimen is and always has been, but this year the yellowing on the middle pad is the result of too much sun. Some of the other discoloration, those spots, are from bites from a nasty beetle that I can’t seem to keep off the plants all the time.
It has been my experience that cactus with a thick covering of spines like these don’t burn because the spines protect them.
So if you acquire a new cactus that has been protected from the sun, don’t just automatically plant it in full sun in the middle of the summer before gradually moving it from filtered sun to to full sun. And if you have a tender cactus already planted in the harsh sun of this year’s weather, try to protect it with a square of shade cloth till the sun settles down, and we aren’t dealing with 100 plus temperatures. Sometimes they gradually get their color back; sometimes they don’t. I think watering more is helpful, and I am going to feed mine more, succulents too, and also try a little iron this year, and see if it might help their recovery.
Stay tuned for results.