What’s That Black Stuff Growing on my Bamboo?

What’s That Black Stuff Growing on my Bamboo?

So you bought a beautiful bamboo plant and planted it in your yard.  It grew nicely for the first year or two and now suddenly you have noticed all kinds of black stuff growing on the bamboo.  It’s all over the place, but especially in the creases of the branching.  It’s unsightly and sickly looking, and you don’t know what to do.

aphids on bamboo
Aphids an bamboo

Well never fear, that black stuff growing on your bamboo is what we like to call black sooty mold.  Black sooty mold forms as the result of a fungus growing on the residue left behind on the bamboo.  My experience here in Florida is that this is most common from an aphid or mealy bug infestation, and even more so is compounded by the ants that have formed a symbiotic relationships with them in order to harvest that sweet nectar.

So now that you know what the black stuff growing on your bamboo is, here is my proven method for getting rid of it and controlling it.

  1. Remove the existing black sooty mold.  This is relatively easy and can be accomplished in no time using a water house and some household dish soap.  Simply add the dish soap to a one gallon garden sprayer and thoroughly coat the areas that are covered with the unsightly black sooty mold. Allow it to soak for a few minutes, then blast it off with the garden hose using a high pressure stream of water.
  2. Treat the infestation.  Whether it’s aphids, white fly or some other pest, you will need to treat the bug that is creating the environment that allows the black sooty mold to form in the first place.  After you have cleaned the sooty mold from the bamboo and it has dried, add horticultural oil to your pump up sprayer and apply the mixture to all the branch nodes (typically early in the morning).  Next, spread a good layer of used coffee grounds around the plant and work it into the leaf mulch.  Coffee grounds act like a natural systemic pesticide, and you can get them for free if you are not a traditional coffee drinker from Starbucks and other coffee houses.
  3. Regular maintenance.  Keep a watchful eye out for any pests, in particular those pesky little ants.  As I mentioned above, ants love the nectar left behind by the aphids, so this is a sure sign that you are on the verge of another infestation.  Regular applications of horticultural oil and coffee grounds will help to minimize your chances incurring just such a thing and thus keep your bamboo black sooty mold free!
ants harvesting nectar from aphids
Ants harvesting nectar (photo courtesy Roy Rogers, Tampa FL)

One extreme method for removing black sooty mold from your bamboo is to also remove all the existing culms.  If you should decide to go this route just know that the pests will often go into the ground and wait for the new shoots to come up and thus create a new infestation.  Therefore, treatment of the bamboo after the culms have been removed is still necessary to eliminate the pests.

One final solution is to get rid of that species of bamboo.  Of the fifteen or so varieties of tropical clumping bamboos that I have in my landscape, on the the Bambusa multiplex varieties seem to attract pests that contribute to the formation of black sooty mold.  Therefore, if you are a bamboo lover like myself, simply plant those that are not as susceptible. such as Bambusa textilis mutabilis or Bambusa textilis gracilis.


6 thoughts on “What’s That Black Stuff Growing on my Bamboo?

  • January 31, 2021 at 10:52 pm

    Thank you for the info! I have 5 clumps of B. Textillis RG Dwarf that has what I am now almost certain to be this black sooty mold problem. I haven’t seen aphids or any other pests on the plants, but that doesn’t mean they aren’t there. Is it OK to use these control methods during the winter when the plants are mostly dormant? I’m in zone 9B in western Florida.

  • March 18, 2021 at 12:20 pm

    We have about 80 asian lemon ( i believe thats their name ) clumping bamboo plants approx 8-10ft tall along our property line here in central Florida we planted 10-12 mnths ago.
    80% have taken on this black sooty mold and the leaves just dont look green and vibrant. The stalks have gone from a nice yellow with green stripe to a brown blotchy look which is not on the surface but within the stalk meaning it wont scrape off like the the black soot.
    I treated with neem oil ( I didnt do the dish soap 1st as I just ran across your site with that advice). The neem oil application seemed to help the black soot for a bit but its beginning to rear its ugly head again. The stalks have never cleared up and im guessing that this blotchy look to the stock is permanent damage.
    Im going to try the dish soap, pressure water and neem oil method. How do I address bamboo once they get taller than they are. Obviuosly i wont be able to get the upper branches anymore once they get taller than they are.
    Thank you for any advice.

  • April 7, 2021 at 2:35 pm

    Thanks for the question.

    To be honest I’m not sure how one would address it on areas that are out of reach. You could also try a systemic pesticide which may kill the aphids as they eat the juices from the bamboo. I’ve read that thinning out the stand to allow more airflow through it helps, though I have no data to back this up. Most times it’s a matter of just keeping it at bay, kinda like Asian Cycad Scale…

  • April 7, 2021 at 2:36 pm

    Absolutely, I’d use control measures year round if necessary. You may also try treating with a systemic pesticide as it should kill the aphids as they eat from the bamboo.

  • May 26, 2021 at 4:54 pm

    I have alphonse karr bamboo in my backyard (Sarasota, FL) For some reason, this geographical spot in my yard will not allow bamboo to grow. I have tried to plants, and neither has done well. It will begin to chute, then the chutes die off. I have black sooty mold where the joints of new branches are along with some small white spots. I thought mealybugs, but I looked at one and it is about 1mm and brown, with a bit of white around it. The stalks of the bamboo also have some black patches on them. The FL carpenter ants love this bamboo too. I have tried massive amounts of fungus control/digging up all the old soil and putting in new/pesticides…I’m at a loss…any help would be great. Thanks

  • May 26, 2021 at 5:34 pm

    Hey Steve.

    That certainly is odd about what you are experiencing. I’ve grown bamboo in central and northeast Florida for twenty plus years and I’ve found bamboo doesn’t really care what soil it’s grown in other than it doesn’t like being too wet.

    I’ve seen larger spots on older culms of my Bambusa emiensis viridiflavus that look fungal and I’ll typically just cut them out of the stand. New culms that pop out typically don’t show any signs of this.

    Carpenter ants in my experience are generally going after the dead leaf mass and culms.

    Have you tried a different bamboo in that area besides a multiplex variety?

Leave a Reply

Your email address will not be published. Required fields are marked *