Euphorbias are easy to grow and can take a lot of abuse but eventually the chickens come home to roost, and we get questions.
We have a large – 4-5 ft. – Euphorbia growing in a pot in our living room. Have had it about two years with no problems. Recently I noticed one of its arms is getting a black die-back at the very top. The die-back is dry to the touch and the plant flesh is slightly soft but dry. A few photos are attached. Any thoughts on what this might be and cures for it?
Possibly, I’m not watering enough. I give it about a gallon of water every 3 months or so. It gets about 5 hours of direct sunlight in Half Moon Bay
I welcome your advice and thanks!
It appears to be just one tip, the other branches look fine in the photo. I don’t know what has caused this particular problem. You might want to think if there’s anything different about that one branch – is it the only one getting direct sun? No sun? Is it touching a surface?
It’s possible it has caught an infection, but if the rot has stopped at just the tip it might be just cosmetic damage at this point. You can cut the branch off below the rot, at a slight angle away from the light source, making sure there is no evidence of rot in the branch below the cut. Whenever cutting Euphorbias wear protective clothing – long sleeves, gloves, eye protection – since the milky white sap is caustic. Spray with Hydrogen Peroxide to help the cut heal faster.
In general I would recommend watering every 3-4 weeks. These Euphorbias can handle being WAY underwatered, but only for so long before they start to show damage. Two years isn’t that long yet, but I would water more often. If you haven’t repotted it in 2 years you might also want to try that, into fast-draining cactus soil.