Asked on May 3, 2017

How to get mold off my tree trunks?

Mary BancroftC.B.Sharon


5 answers
  • Jennifer
    on May 3, 2017

    Is it green mold or is it black slime? It makes a difference. Green mold can just indicate a wet winter and you can kill it with a spray of lime/sulfur (Bordeaux) or a copper based fungicide. If it is black, it could indicate a disease which is causing sap to flow from the bark of the tree. You may want to take a picture of it and then ask at a local nursery.
  • Jean
    on May 3, 2017

    is it mold ? or are they lichens?
    is it growing on the vertical trunks , or on spreading branches
    how are the trees growing, otherwise? are they leafing out, flowering, putting out new growth? are they young or old trees?
    and...what is the climate like?

    Lichens are, for the most part completely harmless - they're not parasitic, like mistletoe is, and they do not add weight to branches, like moss can.

    scrubbing the tree down with a stiff-bristled brush, and then pruning to let in more light and air is usually enough, unless there's something else going on (a dogwood that is dying from anthracnose , or a fruit tree with a fungal infection will also develop lichens, because they like the same things.)

  • Sharon
    on May 3, 2017

    If its moss growing up the tree, I get Moss Out in the shaker and apply it.
  • C.B.
    on May 4, 2017

    Good questions Jean! Ventilation or air circulation around plants is very important, especially trees. If there are bushes growing close to the trees MUST prune back the plants to allow the air to pass through. IF the tree is may be dying due to it's age...especially if it is peeling bark off [as with cottonwood trees & alders]. More information & pictures would be helpful.
  • Mary Bancroft
    on May 4, 2017

    If it's black sooty mold it means scale, identity and spray as needed. Oil spray. If it's lichens, the tree is thin, and they love light. Fertilize! A good fertile tree will be to thick to not support the light needed. No scrubbing required. A good basic organic fertilizer, use a trench spade to dig deep holes and back fill with organic! Not chemical fertilizer. Plant tone by Epsoma is good.
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