Does Triclopyr Kill Grass?

Triclopyr is a common “selective herbicide”. It is most often advertised as safe for use on lawns or grasses. The problem is, not all plants people consider to be “grass” are technically a grass. Further, plant structures aren’t all that simple and at some level, all poison is poison. Below are a few guidelines to keep your lawn safe if you choose to apply triclopyr as well as a few situations in which it should never be used.

Does Triclopyr Kill Grass?

No, triclopyr doesn’t kill most types of “true” grass. Triclopyr is a selective herbicide that is meant to ignore grasses and only focuses on broadleaf or woody plants if used as directed. The thing is, this doesn’t mean it’s harmless for your lawn, even if your lawn is 100% a true variety of “grass”, and if your lawn happens to be made of, say, Zoysia or St. Augustine, then triclopyr will kill your lawn.

What Does Triclopyr Do to a Lawn?

Triclopyr mimics the plant growth hormone “auxin”. The plant then grows out of control. Sometimes this growth is visible, but most often the plant dies as growth at a cellular level cannot hold the proper structure. This hormone is found in plants in different concentrations and some plant life is more susceptible to disruption of this hormone. That is how triclopyr is able to be selective. However, this selectivity isn’t foolproof and, as you will see below, can still lead to the death of a lawn if the type of grass that lawn is made up of isn’t one of the few grass types triclopyr will spare.

Related Article: What Kills Grass? A Comprehensive List

Will Triclopyr Kill Grass?

While triclopyr is a selective herbicide, that doesn’t mean all types of lawns are safe. Many lawns are filled with plants people call “grass” but that aren’t technically classified as true grasses in the same sense that the marketers of triclopyr are using this word. Below are a few common grass types and how triclopyr will affect each of them.

Does Triclopyr Kill Crabgrass?

Yes, triclopyr will kill crabgrass though it may take longer than a non-selective herbicide. Crabgrass is one of those “grasses” that has a different structure than what a true grass will have. It also has broader “leaves” or blades making it more susceptible to the effects of triclopyr application.

Does Triclopyr Kill Zoysia Grass?

Yes, triclopyr can kill a zoysia lawn. Zoysia is another type of grass that triclopyr will target and eliminate. Nearly all grasses classified as “creeping” are likely to be susceptible to triclopyr. Even if the zoysia lawn is not killed outright, it can be weakened in such a way that a sudden fungal or parasite infection is likely to wipe it out.

Does Triclopyr Kill St. Augustine Grass?

Yes, triclopyr will kill St. Augustine Grass. Due to the structure of St. Augustine grass, triclopyr can adhere to the blades, be absorbed into the plant, and cause it to grow and mutate. An entire lawn of St. Augustine can be brought down in as little as a single week.

Does Triclopyr Kill Bermuda Grass?

Triclopyr should not kill a Bermuda grass lawn, as long as that lawn has been well established for several years. All herbicides have the potential to kill nearly any plant, even if they are selective. Triclopyr, if used infrequently and in a low concentration, should be fine for a Bermuda grass lawn.

Is Triclopyr Safe for Lawns?

As noted above, not all types of lawns or “grass” are safe from the effects of triclopyr. Even when triclopyr is safe for use on a type of grass, it can still pose a problem to the health of that grass if it is used too often. Be sure to follow all dosage instructions on the specific triclopyr product you pick up for best results.

Triclopyr should also never be used on a young lawn or a lawn that has been established for less than 2 years. Triclopyr can also be a danger to bushes, trees, and other plants inside your yard so care should be taken to spray at least a foot away from these ornamental plants.

Further, it’s a good idea to only use triclopyr once a year or less as triclopyr can stay in the soil for well over a year under certain conditions, according to tests conducted by the EPA. Triclopyr should also be used several days before any pets or children are allowed to be in that yard to prevent any accidental skin exposure or inhalation of the chemical.

Triclopyr Can Be Safe For Lawns if Handled Appropriately

Triclopyr could be a good tool to use if you happen to have a heavy weed infestation in a long-established lawn. Still, using triclopyr if you’re uncertain about the health of your lawn or its makeup can be risky. Triclopyr can kill many types of grass and a milder weed control method could come with fewer potential long-term side effects.