Black Spots on Euphorbia Trigona

9 years ago

A couple weeks ago I noticed a nickel sized black spot on the base of this Euphorbia Trigona. I cut it off until I was into healthy tissue, but then noticed another one further up the next day, which I also cut off. I started wondering if maybe it was a root problem so even though it's in gritty mix, I unpotted it and found perfectly healthy roots. The areas I cut are starting to heal, but now I noticed black spots around the edges of them and I continue to find small black spots on the arms of the plant. Does anyone have any idea what the issue is? I figured if it was a rot issue, I'd have noticed some rotting roots, but they were perfectly healthy. If the wound at the base doesn't heal properly, I'm thinking about just chopping it off completely and starting new roots. Any advice on the cause of the black spots would be greatly appreciated.

Featured Answer

Lauren (Zone 9a)

9 years ago

I have a few of these and reroot them easily. Big ones will reroot. I stick them in dry soil and walk away.

Once I rooted some in water, and that worked fine too.

also, mine have a bit of the same kind of damage, but they are doing okay. I think the stalks were sunburned.

These plants are tough as nails. Just let the cutting callous, stick it in dry soil, perlite, or pumice and forget about it until you see new leaves popping up or it starts to feel a bit more rigid.

Sort by:Oldest

Comments (8)

Sans2014
9 years ago
last modified: 9 years ago
Hum, has anything changed in the plants environment recently? You might want to also post this in the Cactus and Succulent forum too.
Josh
Original Author
9 years ago
Well, I did cut the tops off about 3-4 of the tallest branches a few weeks ago. It was early, but it was getting too tall to put in the sink to water it. I can't imagine that would cause those black spots though. Also, the black spots penetrate into the tissue, they aren't just on the surface.
Related Professionals
Worthington Landscape Architects & Landscape Designers · Chico Landscape Architects & Landscape Designers · Concord Landscape Architects & Landscape Designers · Victoria Landscape Architects & Landscape Designers · Queens Landscape Architects & Landscape Designers · Middlesboro Landscape Contractors · McComb Landscape Contractors · Houston Landscape Contractors · Morgantown Landscape Contractors · Bridgeport Landscape Contractors · San Bernardino Landscape Contractors · Pensacola Interior Designers & Decorators · Cincinnati Interior Designers & Decorators · Coeur d'Alene Interior Designers & Decorators · Ottawa Interior Designers & Decorators
Sans2014
9 years ago
one would expect any disease to affect the cut area only and spread from there. I was wanting to know if it has been moved, gotten sun burned, rained on, those type things.
Josh
Original Author
9 years ago
No it's been sitting in that same spot for a year.
Sans2014
9 years ago
I'm not sure. I'll ask Stush.
Stush2049 Pitts. PA, zone 6
9 years ago
I don't know either. My best guess is normal conditions with age. Although black spots usually denotes fungus and rot but if hard and I see natural corking going on at the base, it may be ok. Cutting it off may have made it more unsightly but I do understand if it was a disease and better to play safe. All I can say Josh is to keep us posted and see what happens next. Waiting to see who else post with more information. Mine does get those very tiny spots with age but not something that is noticeable.
Josh
Original Author
9 years ago
So I think I'm just going to chop off the bottom and try to start a new root system. Can a base this thick be re-rooted?