Forum home Problem solving

Black Cactus

Can someone tell me what I need to do to save this 30+ year old cactus? Started about 3 days ago and is getting worse


  • Paul B3Paul B3 Posts: 3,065
    Being an arborescent (tree-like) species , it would readily sprout if you removed the blackened stem above the two larger left-hand branches .It will look odd ,but should recover .
    Leave to callous for several weeks , then in the Spring place in as bright a position as possible .
    There is no cure for stem-rot !

    (How large is the plant ? At thirty-years it should be a large multi-branched specimen).
  • It’s 6’ tall
  • Paul B3Paul B3 Posts: 3,065

    The black-stem rot is often caused by too much warmth during the Winter months ; combining this with much lower light conditions often makes the newer growth susceptible to fungal attack , which is what the blackening is . Kept cool and dry during this period is more beneficial . My plants are kept just frost-free in a greenhouse ; dry completely (not a drop) from October to April ; vents are opened on milder days during Winter.
    From what I can see your plant is a worthy specimen of Echinopsis (Trichocereus)  cuzcoensis .
    In their Peruvian habitat these reach immense proportions ; during their dormant period they are cool and dry . Rainfall is sporadic but heavy during the growth period .
    The tree-like manner of growth enables them to re-grow new branches following damage to their stems ,(which is frequent!) ; don't be worried about it not re-growing should you cut off the blackening stems where I suggested .
    I would 'bite the bullet' and go for it ! You risk losing the entire plant otherwise :o

    Good luck !
  • I cut it off as you suggested, about broke my heart. So if it keeps going down then I need to try and cut lower? By the time I saw you message it was almost to the arms so I hope I went far enough
  • Paul B3Paul B3 Posts: 3,065
    I would remove as much of the blackened stems as necessary ; these plants are multi-stemmed as I said earlier . Just keep it dry for a while , give the wounds a chance to callous , place in a bright sunny place in Spring and hope for the best !
  • Thank you so much
Sign In or Register to comment.