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Protect trees from herbicide drift

Farmstead Forest: Herbicides are a part of modern ag, but there are steps producers can take to protect trees and windbreaks from damage.

Curt Arens, Editor, Nebraska Farmer

June 7, 2024

4 Min Read
Brown leaves on tree branch
DYING BACK: There are many symptoms of herbicide drift damage to trees that are also common symptoms of disease, weather and insect issues. Contact your local forest service, Extension office or state department of agriculture for help in identifying drift damage. Also, read herbicide labels carefully to avoid issues around sensitive sites and susceptible trees. Derek Broussard/Getty Images

Herbicide drift damage is a common issue, especially with broadleaf trees in farm country. You can spot such damage from deformed foliage such as leaf cupping, curling and twisting; stunted or twisted stems; defoliation and branch dieback; discolored foliage; or stunted shoots and leaves.

While these are signs of potential herbicide damage to trees, there are other issues, such as insects and diseases, that can cause these same symptoms.

Some of your farmstead or windbreak trees may be more susceptible than others to herbicide damage. I’ve always found hackberry trees to be one of the first to exhibit symptoms, serving as a “sentinel” tree. Other sentinel species, particularly in areas like southeast Nebraska, might include red bud and oak, just to name a few.

Understand herbicides

All types of herbicide formulations can cause drift damage to trees, including volatile products like 2,4-D and dicamba, which form a gaseous vapor — even days after application — that can volatize during warm temperatures and move great distances from the application site to cause damage to off-target plants.

Contact herbicides such as glyphosate are thought to be less dangerous to trees, but remember that these are nonselective and can kill any plant they encounter. Care must be taken when applying such herbicides around sensitive plants and young trees. Besides, many glyphosate products also include additional residual active ingredients that can be taken up by roots.

Related:Deal with suckers on trees around farm

According to a Nebraska Forest Service (NFS) release by Laurie Stepanek, Justin Evertson and Kyle Martens on this topic, it is right to be particularly wary of products labeled for control of brush and woody weeds, because they can normally cause significant damage to trees.

“Even trees located some distance from the application site may be affected since tree roots can extend well beyond the canopy of the tree,” the release notes.

Evertson, green infrastructure coordinator for the Nebraska Statewide Arboretum, recommends particular care in applying products containing triclopyr (Garlon, etc.) and picloram (Tordon) around important specimen or farmstead trees and woodlands.

“They are both used in woody brush control and are very hard on trees,” he says. “Picloram is especially problematic, because it can be carried to non-target trees through drift or via soil leaching, and it can persist in the soil for many years.”

While ag field operations are often blamed for tree herbicide damage, there are several lawn and household herbicides used to control dandelions and other lawn invasives that are quite often the true cause of injured trees.

What can we do?

NFS staff suggest several tips for reducing the herbicide damage potential to your trees, or to other sensitive sites like area vineyards or neighboring plant and tree nurseries:

Follow directions. It should go without saying, but read and follow all directions on the labels of herbicides — whether it is in the field or around the farm — especially when using those herbicides that are known to vaporize and runoff.

Know sensitive sites. Pay attention to the surroundings when applying herbicides. In Nebraska, you can visit driftwatch.org to learn of sensitive sites like vineyards, organic farms, native woodlands and plant nurseries near the location for herbicide applications; and take particular care around sensitive trees around your own farmstead.

Be aware when applying to lawns. Homeowner herbicides include many of the same active ingredients that can cause damage to trees. Be aware of these herbicides and understand the potential when applying them to lawns and gardens near farmstead trees.

Go to fall. This isn’t always possible, but the time of new tree growth in spring is the time of most herbicide problems. Moving some herbicide applications to fall, whenever possible, can greatly reduce potential damage.

Avoid wind. Warm temperatures and windy days can easily cause problems with drift, so as an applicator, be sure to monitor temperature, wind speed and direction to avoid drift issues.

Coarse-spray. Adjust sprayer nozzles to a coarse-spray droplet size around sensitive areas, rather than a fine droplet size.

Don’t overapply when treating stumps. If you are treating stumps around areas of sensitive trees, be careful not to overapply because the treatment chemicals can move in the soil from stump roots.

Think long term. It is true that many trees, particularly young trees, can be killed by one misguided herbicide application, but it is often the case that these trees can recover from repeated light damage. However, if the same damage is repeated year after year, it still eventually can shorten the life of any susceptible tree.

For help in identifying herbicide drift damage, contact your local forest service, Extension office or state department of agriculture.

Read more about:

Herbicide

About the Author(s)

Curt Arens

Editor, Nebraska Farmer

Curt Arens began writing about Nebraska’s farm families when he was in high school. Before joining Farm Progress as a field editor in April 2010, he had worked as a freelance farm writer for 27 years, first for newspapers and then for farm magazines, including Nebraska Farmer.

His real full-time career, however, during that same period was farming his family’s fourth generation land in northeast Nebraska. He also operated his Christmas tree farm and grew black oil sunflowers for wild birdseed. Curt continues to raise corn, soybeans and alfalfa and runs a cow-calf herd.

Curt and his wife Donna have four children, Lauren, Taylor, Zachary and Benjamin. They are active in their church and St. Rose School in Crofton, where Donna teaches and their children attend classes.

Previously, the 1986 University of Nebraska animal science graduate wrote a weekly rural life column, developed a farm radio program and wrote books about farm direct marketing and farmers markets. He received media honors from the Nebraska Forest Service, Center for Rural Affairs and Northeast Nebraska Experimental Farm Association.

He wrote about the spiritual side of farming in his 2008 book, “Down to Earth: Celebrating a Blessed Life on the Land,” garnering a Catholic Press Association award.

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