What is Garlon RTU?

There are many herbicide options that can be used to control the growth of unwanted plants and trees. Having all the information about a given herbicide is important to pick the most suitable one. Furthermore, how to use a herbicide correctly can make a huge difference in the final outcome. Let’s take a look at everything you need to know about Garlon RTU.

Garlon RTU is a synthetic, systemic, ready-to-use herbicide manufactured by Dow Agrosciences. Its main component is Triclopyr BE ester and it is ideal to control the growth of hard-to-kill deciduous trees including conifers.

What is Garlon RTU?

Garlon RTU is the registered trademark of Dow Agrosciences. It is a ready-to-use product majorly used for controlling the growth of hard-to-kill deciduous trees. The recommended ways of delivery include basal bark treatment and cut stump treatment.

Garlon RTU does not require any mixing and can be used straight out of the box, it is a selective herbicide which means that it is only effective on the species it is applied on. The herbicide can be used year-round but is not as effective if there are frost, dew, or water on the treated plants and/or trees.

The main active ingredient in Garlon RTU is Triclopyr BE ester. It is non-residual in the soil and is only considered slightly toxic to humans. It has to be noted that it can cause severe eye damage if it comes into contact with the eyes.

What Tree Species is Garlon RTU Effective on?

Garlon RTU is registered to be effective on Alder, ash, aspen, basswood, beech, birch, blackberry, buckthorn, cherry, chokecherry, cottonwood, dogwoods, elderberry, elm, hawthorn, hickory, hop hornbeam, honey locust, maples, mulberry, oaks, pines, poplar, red maple, sassafras, sumac, sycamore, tamarack, wild rose and witch-hazel.

What is the Best Application Method for Garlon RTU?

The recommended application methods for Garlon RTU are basal bark treatment and cut stump treatment.

Basal Bark Treatment

For use with Basal Bark Treatment, make sure there is no frost, water, or snow near the base or on the trunk of the tree. Spray the herbicides using a backpack or portable sprayer directly onto the trunk of the tree. Barring any moisture exposure, it can be used all year round.

It should be noted that Garlon RTU is effective on trees through basal bark treatment when the basal diameter, or the diameter of the trunk, at breast height is less than 6 inches or 15 cm. It is most effective on trees with diameters of less than 3 inches or 8cm.

Cut Stump Treatment

While using with cut stump treatment, Garlon RTU ensures that no offshoots or sprouts grow from a cut stump. While the manufacturers suggest that it can be used with both old and newly cut stumps, experts recommend using it as soon as a tree is cut down.

The best method to apply it is by either using a portable sprayer or a paintbrush. The former is recommended if you have to apply it to a large number of trees.

No matter which technique you are using, do not spray the chemical on a windy day as it can get carried long distances and affect non-targeted vegetation.

How Does Garlon RTU Work?

Garlon RTU contains Triclopyr BE ester with a concentration of 144g/L. Triclopyr works by mimicking a growth-regulating chemical called auxin.

Auxin is responsible for regulating or controlling the growth of trees. Triclopyr works by increasing the amount of auxin present within a plant. Disturbed auxin levels will result in uncontrolled growth, eventually leading to death of the targeted plant.

When Garlon RTU is sprayed on the stump or the trunk, it penetrates the tree to reach the cambium layer. It is then transported to the rest of the tree using its vascular system.

How Does Garlon RTU Interact with Soil?

The main chemical within Garlon RTU is Triclopyr. Triclopyr adsorbs with the soil particles which reduces any chances of runoff. It is majorly degraded through sunlight and microbial action. Once bonded with the soil, it only tends to stay within the top 20-30 cm of the soil which reduces the chances of water contamination.

The average half-life of the chemical in the soil is between 30-46 days.

How Does Garlon RTU interact with Water?

Garlon RTU should not be used with water or near any water bodies. It is not approved to be used on wet surfaces. Triclopyr ester is again dissipated majorly through sunlight in this case because of the lack of microbial presence, the half-life is slightly longer when compared to soil.

Up on contact with water, Triclopyr goes through hydrolysis which converts it into triclopyr acid.

What Are the Major Uses of Garlon RTU?

One of the major benefits of using Garlon RTU is its ineffectiveness on grass. This makes it ideal for uses involving vegetation control near electrical utilities, highways, railways, pipelines, etc.

Is Garlon RTU Harmful to the Environment?

Garlon RTU is not considered to be very toxic to the environment. Because of the low vapor pressure of the main ingredient Triclopyr. The chemical only has low to mild toxicity in fish, birds, and other grazing mammals.

Upon consumption by animals, triclopyr is quickly released from the body through urine within 24 hours. It doesn’t bio accumulate in animals other than fish. Prolonged exposure to birds has resulted in thicker eggshells.

Because of the short half-life, the chemical is not present in the soil for prolonged time periods. On the other hand, it is present in plant tissue until it completely decomposes.

Is Garlon RTU Toxic to Humans?

Garlon RTU is not known to be toxic to humans.

Accidental oral consumption during handling will not lead to any long-term harmful effects. Short-term effects include jitters, headaches, nausea, and an upset stomach. There is also no evidence that exposure to Garlon RTU in mammals leads to any carcinogenic, mutagenic, or teratogenic effects.

This is because mammals do not metabolize Triclopyr. Usually, after consumption, a major portion is simply excreted from the body without any changes.

Garlon RTU or Triclopyr has extremely low skin absorption, only about 2% of the amount can be absorbed through the human skin. Short-term exposure has no effect on humans, but prolonged exposure can lead to allergic reactions including redness and irritation.

The users should avoid any sort of contact with the herbicide in their eyes. Garlon RTU can lead to severe eye damage which can also be permanent. It is extremely important to use proper safety equipment while handling the chemicals.

What are the Safety Precautions While Handling Garlon RTU?

It is recommended to wear goggles or other protective eyewear along with chemical-resistant gloves, an extra layer of clothing that should be discarded or washed right after use. Make sure not to mix these clothes with your everyday laundry.


Garlon RTU is a ready-to-use, systemic herbicide whose main component is Triclopyr Ester BE. It is a selective herbicide and is ideal for controlling the growth of hard-to-kill deciduous trees. It is manufactured by Dow Agrosciences and is ideal to use along with basal bark or cut stump treatment.

Scroll to Top