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Tuesday, June 21, 2011

New herbicide for lawns seems to kill more than weeds

Two spruces in Saline
Conifers scattered throughout Saline, Plymouth, the U-M campus, and perhaps much of the U.S. have taken a hit from a new herbicide released by DuPont called Imprelis. The selling point of this new weed-killer was that it was wouldn't harm trees. The problem is that it harms trees, particularly norway spruce and white pine. It has also resulted in conspicuous yellow streaks in lawns (so I guess it harms grass also). 

So what  happened? Obviously the company didn't intend to release a product that would kill non-target plants. Probably they wagered that the precipitation would be within a certain range, but the heavens went overboard, leading to the quick and deleterious uptake of the product by woody ornamentals. Obviously the recommended dosages were too high. But scaling back on the dosage would have meant that customers wouldn't have to buy so much product. Hmm. Ultimately one must wonder who is going to pay for the damage. Some individuals are claiming that damage to woody plants on the University campus is not restricted to conifers.


  1. Our local lawn care service is coming out to take pictures of our 20' Norway spruce that are browning out. They were upfront about the use of Imprelis and told me that they have already contacted their lawyers and Dupont. Articles I've read regarding Dupont's response suggested they are already waffling! Driving down Maple Road from Saline to Ann Arbor you can see many affected trees.