The main thing that these two products share in common is that they are both systemic herbicides, meaning that once they come into contact with plant material they will not only damage that part of the plant, but the whole thing, right down to the roots. This is great news if you have weeds that (annoyingly) keep resprouting after dying back.
You might think that you can pick up either of these herbicides to do the job, but there are a few things you might want to consider when comparing Glyphosate vs Triclopyr. You could be wondering if can they be mixed together to form one super herbicide, or when should one of them be used in place of the other? Read on to find out more about each product, their compatibility, and what sets them apart.
The Difference Between Glyphosate and Triclopyr
Apart from the tricky pronunciation, the major difference between Glyphosate and Triclopyr is that while Glyphosate will kill all plant species that it comes into contact with, Triclopyr will only affect certain types. Glyphosate kills all, triclopyr kills some, pretty easy to remember.
Yet there is more to it than that. Glyphosate and Triclopyr are defined as systemic herbicides, meaning they disrupt the plant’s biological processes, moving through the plant and down to the root. Hence, they mess with how the plant operates in order to survive.
Glyphosate inhibits vital protein production, while Triclopyr disrupts cell division and expansion.
See a quick comparison of the two in the table below:
| Glyphosate | Triclopyr | |
|---|---|---|
| Target | Broadspectrum | Selective |
| Toxicity to Humans/Animals | Low to None | Low to Moderate |
| Killing Action | Systemic | Systemic |
| Time to Take Effect | Slower: 7-14 Days | Quicker: 3-5 Days |
| Origins | Synthetic | Synthetic |
Comparing Glyphosate vs Triclopyr
How Are They Applied?
You’ll want to pay special attention to this part, especially when dealing with herbicides that have the capabilities of killing anything they come into contact with.
Glyphosate Application
Glyphosate should be applied to the leaves of the plants you want to kill.
This potent herbicide is best applied as a spot treatment if you want it to kill only specific plants in the vicinity, or as a spray, if you want it to kill everything in an area.
What each person is wanting to achieve through their lawn care varies, so it is important to first decide on what you are wanting the herbicide to do for you, before applying it.
Is it for a couple of pesky weeds popping up here and there? Or is it time to start again and take out everything?
Just remember Glyphosate is best applied on a windless day to avoid drift and watch for any drips or spills from the spray can while walking across the lawn. Not only will your wife be able to track your movements from the trail you leave behind, but you will be in a world of trouble if she sees you took a shortcut through her flower bed!
Triclopyr Application
Now you really don’t have to be quite as careful with the application method of Triclopyr. You can apply it as a spray, paint it on stumps (it works through tree bark) or you can even inject it into trees or the surrounding soil.
I wouldn’t go skipping around the garden making it rain with Triclopyr, expecting every unwanted weed to just die and leave behind the garden of your dreams though. Even though Triclopyr can be sprayed and used as a general application it may still negatively affect some plants you wish to keep. For instance, MOST grasses are not affected by Triclopyr, but not all. Kikuyu shows signs of damage when sprayed with Triclopyr, and can be killed by repeated applications.
And you should be aware that there are variations of Triclopyr. For example, the Ester variation is used more commonly to penetrate the bark of wooded plants, while the Amine variation is used in turf application as it has less of a drift to it. So make sure you choose the variation that best suits your intended purpose.
When to Apply?
The question of when, and not just how, to apply herbicides should also be taken into consideration. Glyphosate and Triclopyr are both post-emergent herbicides, hence the best time to apply is early to late spring, when seedlings are actively growing but not yet mature. Do not mow for 3 days before application.
While the plants are growing they will actively draw in more of the herbicide, allowing it to be more efficient in killing the plant.
What Weeds Do They Kill?
Glyphosate kills broadleaf plants as well as grasses. The term “broadleaf” refers to any plants that have a flat, relatively broad surface and are most commonly marked with a network of visible veins.
Triclopyr works on broadleaf plants and plants with woody stems. It is commonly used to spray brambles and nettles growing in areas where you are trying to promote grass growth. That is not to say it doesn’t kill all grass species, just that most grasses are not affected by it. Which makes reading the label and knowing your grass species just that little bit more vital.
How Do They Work?
Glyphosate Action
Prevents plants from producing some proteins that are vital for plant growth, which in turn stops a specific enzyme pathway. That enzyme pathway is called the shikimic acid pathway.
In essence, the plant is starved of essential vitamins, minerals, and amino acids that it needs to perform everyday functions, leading to death.
Triclopyr Action
Triclopyr is like a hidden spy within the plant. It mimics a specific growth hormone (auxin) of the plant, causing uncontrolled growth which overwhelms the plant, ultimately leading to its death. Simply put, it strangles the plant from the inside.
How Fast are Results Visible?
Glyphosate Results
The first signs of effective treatment will be the wilting of leaves which generally occurs within 12 – 24 hours of application. The plant including the roots is completely dead within 7 to 14 days.
It is important to mention that Glyphosate products should be given sufficient time to infiltrate the plant and effectively kill it. Glyphosates rely on the plant’s internal biological processes to carry this out. Once an application is made, it is important to leave the plants and do not cut them or pull them out for at least 10 days after application.
Triclopyr Results
Wilting and yellowing of leaves should be visible within 48-hours of application of Triclopyr. The entire plant is killed within 3 to 5 days.
Remember though, there are varieties of Triclopyr and they perform differently. The Ester variety can take up to 2-weeks before any signs of negative growth are shown. After 4-weeks if the plant has still not died then a follow-up treatment may be necessary.
Is One Safer than the Other?
Glyphosate and Triclopyr share a lot of safe characteristics when it comes to toxicity. Perhaps the most important is that both do not show signs of bioaccumulation (becoming concentrated inside living organisms).
Glyphosates are non-irritating to the eyes and skin. All forms of Triclopyr have low dermal toxicity, however, it might cause sensitivity with repeated exposure. The Ester form can also cause irritation to the eyes and the salt form can cause eye damage.
Glyphosate has improbable carcinogenic properties, when used as per label instructions. Triclopyr is unclassifiable as a carcinogenic.
Both are low in toxicity, however, one should be especially careful when working with Triclopyr not to get it in your eyes.
When is Glyphosate a Good Option?
Glyphosate is the go-to option when you want to start again or clear a specific area and completely change the plants growing there. With it being non-selective, its effectiveness is broad and unselective. Examples of suitable use cases would be when you want to clear an entire piece of land, or once an old flower bed is pulled out, kill anything that sprouts back up so as not to compete with anything you subsequently plant.
Another good time to grab the Glyphosate is when your lawn has crept someplace where it was never intended to occupy, for instance in between the cracks of your paving or walkway. This is how I’ve mostly used it and my patio area looks all the better for it!
When to Choose Triclopyr
The main pro to using Triclopyr is that it doesn’t damage most grasses, so it is the best choice to control woody seedlings and broadleaf weeds emerging in lawns.
Glyphosate is not as good at killing woody plants as Triclopyr, and fewer plants have resistance to Triclopyr vs Glyphosate.
Triclopyr may take a few days to kill a plant completely but still works faster than glyphosate.
Can I Mix Glyphosate and Triclopyr?
Yes, they can be mixed. They form a non-selective, broad-spectrum herbicide that is best suited to cases where the target plants can be individually spot treated. There are no known instances where the mixed solution is less effective than either one of the ingredients on its own.
Each one used on its own has certain species that it is ineffective against (glyphosate doesn’t work on autumn olive and Oriental bittersweet. Triclopyr alone doesn’t work against shrub honeysuckles for instance.) The combination will take care of all of these exceptions, meaning less walking around for repeated treatments to problem weeds.
An incompatibility occurs between the two herbicides combined at high concentrations and solid molecules will form in the spray mixture. You can either overcome this by only mixing small carrier volumes of 15 gallons per acre, and also by avoiding storing unused mixed solutions. The second way to overcome this is to add triclopyr first to 75 percent of the final mixture volume and mix it in completely before adding Glyphosate. This makes sure that the two herbicides only come into contact with each other when they are already diluted in the final mixture.
The drawback is that using very low volume application methods is not suitable and it is recommended to mix 15 gallons or greater at a time. So mixing a small hand spray bottle of the two herbicides would be problematic, and if you only have a few dandelions sprouting up in your lawn it is best to choose either one of these to use on their own.
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