Diagnostics: Canker on Heptacodium

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  Today I met with OSU horticultural great Kenny Cochran at his garden in Wooster and we enjoyed checking out everything from his sweet cherry tomatoes to the two-toned leaves of his silver linden tree. One plant which gave us concern was a seven-son flower tree (Heptacodium miconoides). More on the tree later in an upcoming Tree of the Week post, but some stem dieback amidst the just-coming-into-flower panicles is what got our attention. Shoots with brown leaves amidst perfectly healthy-looking shoots with green leaves. 


roughened area on bark from canker


  Kenny got out the saw and cut off a major branch and we saw the roughened, discolored area on the stem that is best described as a symptom known as a “canker”. Cutting into the stem there was a clear-cut edge of discoloration in the otherwise healthy-looking greenish-whiter plant tissue. We decided: off to the OSU Plant and Pest Diagnostic Clinic with a sample from the area of gradation from healthy to affected, in order to culture for possible canker fungi.


dieback on heptacodium


  Not today, but a freshly cut sample will be taken on Tuesday morning so it does not sit in the mail over the weekend. Or perhaps I shall even take it to Columbus on Wednesday (September 7), when I attend the Urban Landscape Pest Management Workshop at OSU, one of the Ohio Pesticide Commercial Applicator Recertification Conferences. And certainly, we shall have samples on view at our 83rd Annual Plant Diagnostic Workshop in Wooster next Friday, September 9, along with other fascinating diagnostic conundrums. So much diagnosticating, so many times.