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Thursday - August 21, 2008

From: Palo Cedro, CA
Region: California
Topic: Non-Natives
Title: Fungus on trunk of non-native weeping willow in California
Answered by: Barbara Medford


I live in Palo Cedro, CA and have a weeping willow tree with with what appears to be be some type of fungus growing all over the trunk of the tree. It is a brown color and can be broken off in big chunks. It is not part of the tree or root system. Could you please give me your opinion on what it is and if there is anything I can do about it? It is about 20 feet tall and about the same distance wide. It is a beautiful and healthy tree aside from this problem. Thanks for any help you can give. Don


We found a couple of plant diseases that particularly seem to like members of the genus Salix, or willow. The particular willow you have, of course, is not native to North America, but to China and is Salix x sepulcralis. Willows are weak wood and disease prone, fast-growing but short-lived. At the Lady Bird Johnson Wildflower Center, we promote the use and propagation of plants native to North America. In this particular case, it probably doesn't matter if the plant is native or not.

The two diseases that we found that we believe fit the description of symptoms that you gave us are Crown Gall  (University of Maine Pest Management Labs) and Canker (Iowa State University Extension site on Fast Growing Trees).

Images of Canker on willows

Images of Crown Gall

From the description you gave us of the problems your tree was having, we would say the best thing to do is get it down and disposed of before the disease can spread to other plants in the area. If you prefer, you might have a trained arborist look at it, and see if it's worth the effort to try to save it.


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