Herbicides: Kill Weeds, Not Trees

For many trees and shrubs, the summer months are a period of rapid growth. The same can be said for weeds around your yard. While it may seem like a good idea to grab a spray bottle of weed killer, it’s important to understand these chemicals and how they can affect your property and everything living on it.

Store-bought weed killer is an herbicide, meaning it’s designed to be toxic to plants, and that means ALL plants. During the summer, when herbicides are used most frequently, our staff often sees the effects of incorrectly applied chemicals causing damage to and even killing trees and shrubs. 

Herbicide damage to trees is often the result of improper handling and application of the chemical. The result depends on the severity of the application and which specific chemical is applied, but there are some telltale signs that weed killer is the culprit. Affected leaves will often shrivel up into a cupped and deformed appearance. New growth can be stunted in size and development and will be tightly clustered. They can often have a hard “plastic-y” feeling.

Once a tree has been affected by weed killer, there is little that can actually be done to reverse the damage. Remember, these chemicals are designed to kill vegetation! Depending on the severity, it is often recommended to wait at least a season to see how the tree handles the exposure. Watering the soil regularly can help flush some of the chemicals out of the ground as well.

The next time you’re planning on ridding your yard of weeds, follow these steps to ensure that there are no unforeseen casualties:

• When possible, pull weeds by hand.
• Spray herbicide on specific weeds, not over a broad area.
• Never spray on a windy day. Wind will carry herbicide onto nearby trees and shrubs.
• Avoid any chemicals on the roots or trunk of your trees and shrubs.
• Try to avoid treating the area within the drip line of a tree (the area underneath a tree’s canopy).