Thursday, August 19, 2010

Glyphosate damage on ash tree.

This photo of an ash tree shows symptoms of glyphosate uptake. Glyphosate, initially sold as Roundup by Monsanto, is now available in generic form at many farm cooperatives, and retail businesses.  When this product is misapplied it can cause damage.  In this case the owner sprayed glyphosate to control weeds at the base of the tree last year.   These symptoms appeared this year.

Glyphosate may drift onto the buds or be taken in through green tissue at the base of tree . 

Symptoms of glyphosate toxicity the year after glyphosate uptake results in clusters of leaves where shoots should develop.  I've seen these same symptoms on trees in local retail nurseries where the wholesale nursery applied glyphosate to control weeds around the trees the previous year. These symptoms are also occasionally seen on grape vines when glyphosate is used to control weeds at the base of the vines.

Herbicides should be used with care.  Don't assume they are safe.


  1. I did this to my ash tree, although until I read this posting just know, I did not know the problem was based on anything I had done.

    When the problem first revealed itself three springs ago, I consulted with Bookcliff Gardens, and was told the problem could be the result of an ash borer infestation, but they expressed no confidence in that diagnosis.

    Regardless of their diagnosis, their advised treatment did work. I got a deep root watering spike, attached a fertilizer jar, filled it with Miracle Grow, and pumped a ton of the mixture into the soil around the roots, moving the spike every ten minutes or so. I did this in the late summer so there would still be some present in the soil in spring, and I did it two years in a row. While some branches did die and had to be removed, the tree thrived, new branches grew, and it is leafy and full again.

    Steve Hight

  2. There are a couple of old Plane trees in our town that have similar looking damage from "accidental" (ie stupid) weed management around their roots followed by heavy rain. I'm curious how your ash tree has performed after a full season of growth? Has the new season's growth continued to grow deformed and stunted? Did some sections eventually die? Did epicormic growth develop on main branches as well? The Planes are in the southern hemisphere and are just coming into leaf but much later than other plane trees and these are some of the symptoms I have observed so i was wondering what eventually happened to yours.
    John Atkins

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