JoAnne Skelly: Herbicide bloopers can be deadly to plants

Throughout the years, I have seen or heard some big herbicide bloopers.

A man came with samples of damaged leaves and I told him it was herbicide damage. He insisted it couldn’t be because where he used herbicide wasn’t anywhere near these plants. He exclaimed, “Come to my house and look. You will see I’m right!” I was curious what else it could be, so I went.

When he showed me his gardening shed, I saw an herbicide on the shelf that would cause the damage his plants had. He told me he applied it in a specific watering can designated just for that herbicide and never near the plants. In the end, we found out his father, who lived with him, was trying to be helpful and fertilized all the damaged plants with a water-soluble fertilizer he mixed in the same watering can that was supposed to be used only for the one herbicide. The residual herbicide in the can did the damage.

Another time a man came to the office almost in tears. He had some pesticide left in a sprayer and thinking it was an insecticide, he sprayed all his fruit trees with it. A couple of days later, he remembered that it wasn’t an insecticide, it was Roundup, a non-selective herbicide. He was frantic to know what he could do to save the trees. Although washing the chemical off after a couple of days would probably be ineffective, it was all I could suggest. Unfortunately, his trees were going to suffer and possibly die.

Once, I was called out to a hotel property to look at damaged trees. It looked like soil sterilant damage to me. I noticed that the trees were below banks that had no weeds growing on them. I asked the property manager what he used to keep the slopes so weed free. He did use a soil sterilant but assumed since it was above and a distance away from the trees, they would be alright. He hadn’t counted on heavy rains washing the chemical down into the roots of the trees.

I also have seen herbicide damage to trees in parks from chemical that vaporized off the soil and into the leaves after being applied on a hot day. Or, trees sick and dying from misapplied road chemicals. Or, people that used soil sterilants near their roses, flowers and shrubs.

Bottom line is, read the label and follow it.

JoAnne Skelly is associate professor and Extension educator, Emerita at University of Nevada Cooperative Extension. She can be reached at


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