Plant Health Alert - Herbicide Damage

(Updated: July 1, 2025, 9:23 a.m.)
herbicide damage tree

Accidental herbicide damage to landscape plants and vegetables can happen when an herbicide moves from the target site of application to a non-target site. In these instances unintentional plant damage can happen. Avoiding the unintentional damage of non-target plants requires careful usage of herbicides.

Herbicide movement can happen when chemicals wash away in rain or irrigation water. Sometimes chemicals volatilize in hot weather.  Some products can even volatilize several hours after application, so do not apply them if high temperatures (above 85F) are predicted for later in the day. This gas can damage sensitive plants.  Do not spray during temperature inversions when cooler air is trapped at ground level by warmer air above, common during the early evening hours. Herbicides can 'drift' when sprayer mist travels in wind off site. Herbicides that are used on pastures can even pass through grazing animals and end up in manure.

Read The Label! Licensed chemical contractors, farmers and home gardeners should be very careful when using any herbicide on or near residential properties.It is imperative and legally required that pesticide users read the label on every chemical they use. It is the responsibility of the user to read the label and use the product correctly.

Identifying herbicide damage is obvious in some cases. In other instances the damage is more subtle. There are many herbicides with different modes of action that cause various types of plant injury. Glyphosate often turns plants bright yellow. 2-4,D distorts leaves on sensitive plants. There are many herbicides with different modes of action.

Examples For instance, stump killer herbicides with the active Ingredients picloram, 2,4-Dichlorophenoxyacetic acid and triisopropanolamine salt should not be used on residential landscapes. These stump killer herbicides are meant to be used on fencerows, roadsides, right-of-way, and other sites but not landscapes. The chemical is deadly to trees and shrubs at very low rates. The chemicals in these products are very water soluble and move through the landscape away from the application site.

The label clearly states that small amounts of the product can damage surrounding plants. The label also states, "Use --------- Stump Killer on cut trees and branches in forests and non-cropland areas such as fencerows, roadsides, right-of-way, and other sites. Do not apply on residential or commercial lawns or near ornamental trees and shrubs."

Leaves curling on a tree denoting herbicide damage.

A commonly used herbicide containing 2,4-D is formulated as a low volatile ester. However, the combination of spray contact with impervious surfaces, such as roads and rocks, and increasing ambient air temperatures, may result in an increase in the volatility potential for this herbicide, increasing a risk for off-target injury to sensitive crops such as grapes and tomatoes. Under conditions which are conducive to evaporation (high temperatures and low humidity), vapors from this product may injure susceptible crops growing nearby even though the chemical is formulated to make it less volatile.

Small plants and curled leaves denoting damage from herbicides.

Herbicide damage to sensitive plants can happen when herbicides end up in manures that are used for soil amendments. A common herbicide that is used on pastures can pass through an animals digestive system. Manures that are composted for more than a year should be ok to use.

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