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Horticulture/Japanese Maple Spongy Fungus


J Maple with white spongy fungus Pic 1
J Maple with white spo  

J Maple with white spongy fungus Pic 2
J Maple with white spo  
Hello Ms. Tabor,

I have a large Japanese Maple in Marcellus, NY that has 4 white spongy things (fungi?) growing on it.  The fungi are damp with a slight funky odor.  Please see picture attached of the largest one.

Do you have any recommendations for what I should do and how worried I should be?

Hi Drew,

It's not a good sign, I'm afraid.  Most shelf fungus - like Mossy Maple Polypore -attack wounds in trees and decompose the wood.  Some trees live decades with the problem and others don't.  

I would remove as much of the fungus as I could without wounding the tree anew and spray with a fungicide like copper or Daconil (clorothalonil).  Your local garden center should carry these.  It may take repeated sprayings at 2 week intervals.

Since the tree is weak, it will need good care.  That means watering during droughts, regular fertilization, protection from other diseases and insects, etc.

Call your local university or county agent and talk to a plant pathologist.  They may have other suggestions.
Good Luck to you and your tree.


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Susan Tabor


Entomology,plant pathology, agronomy, native plants, useful and edible plants,medicinal plants,landscape design and installation, plant taxonomy and identification, cultivars and varieties, Botany, nutrient deficiencies, plant recommendations and troubleshooting.


35 years as a professional horticulturist and landscape contractor. I have a network of contacts at leading universities and with acknowledged experts in the field. I've restored the landscapes of several plantations, 2 Governors mansions and owned/managed 3 nursery/garden centers. I discovered a new subspecies of Emelia in 1997. I've locally introduced several native or volunteer species into mainstream landscape design.

Morning Advocate The Register Better Homes and Gardens All Experts - Approx 1996-97

Louisiana State University - horticulture David L. Hoffman - California - phytotheraphy

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