We Get Questions
Attached are photos of five cereus plants in our garden, all of which did great in the ground for five months but are now showing signs of distress.
Crested cereus — The first two shots are of the same plant, which has some black spots on top and the trunk has cracked open. This plant is located nowhere near the others.
Night-blooming cereus — We have two, located next to one another. The affliction is showing itself as dark sunken spots on the new growth. In some places these have become holes, all the way through the “fin” of the plant.
Lophocereus — Again, we have two of these, located next to each other but nowhere near the other cereus plants. Similar story — the new growth on top has lots of black spots, some of which are now sunken inward.
These plants are all on mounds, with good soil and drainage. The soil is still moist from recent rains, but not a lot. I’m really concerned that as we head into winter, we may need to strip away the pebble coverage and try to aerate the roots somehow.
The garden has about 30 or 40 plants and all the others look fine at this point. We only live a few blocks from your store — maybe we could pay you to take a look at the situation one morning. Many thanks,
The crested top view looks like it was bruised and is now scaring up from getting whacked or bumped hard. The trunk view looks like beetle or rodent/bird damage, look in the holes and make sure there is not a grub eating the plant from the inside. They can really make a mess inside the trunk, pull them out with tweezers if that is what is going on and squish them. Clean and disinfect the cavity with Hydrogen-Peroxide if it looks “juicy”. Once it has dried out and looks scabbed you can treat with Neem Oil as well. If it looks like it will collect water you will need to make an additional cut in the tissue to create a drain channel. Pooled water will cause major rot issues.
The Lophocereus and Cereus are showing signs of slug and snail damage, which is leading to secondary infections. I recommend that you treat all the damaged areas with Neem Oil and scatter Sluggo through out the garden. Retreat with Neem after a week. If the infections persist there are more aggressive treatment options, but of course they are more toxic and take special handling.
We do make housecalls if you want to schedule one to confirm what I see in the photos.