"The Environmental Protection Agency banned the sale on Thursday of Imprelis, a weed killer introduced this year that landscapers link to thousands of tree deaths around the country." (source: New York Times, August 11, 2011)
Another pesticide is banned from lawns and turf areas after killing of the trees nearby.
"While it has been highly effective at killing clover and broad-leafed weeds like dandelions, landscapers say, nearby evergreens in many cases began dying within weeks of the first applications. Some agricultural experts have suggested that the tree toll could reach into the hundreds of thousands."
Imagine how much it would cost to replace (which you really can't) a big old spruce or douglas fir. In the article they say up to $25,000. Wouldn't you rather have some dandelions and clovers AND your tree alive? I just don't get the need people have to have a weed-free lawn, a rather sterile environment just of spiky grass leaves. Certainly, our pursuit of neatness and control in our gardens brings us more and more toxins and deaths.
Now I wonder how many of the dead conifers you see around here in New Jersey after last summer's drought might have been from landscapers spraying Imprelis on the ground around them.