Best Weed Killer for St Augustine Grass (Top 10)

Are you looking for the best weed killer for St Augustine grass? You are at the right place, we tested multiple weed killers from different companies, and here are the top products for helping you make the right decision.

St Augustin grass is a warm-season turfgrass with a thick and relaxing feel and robust growth.

Since it is prone to weed, among other things, we need to prevent an invasion of weeds before it wrecks your grass. 

Best Weed Killer for St Augustine Grass (Top 10 Picks):

1. Roundup Ready-To-Use Weed & Grass Killer

Roundup has been in the production of herbicides for long enough to be trusted. Their weed killer is one of the best out there:

• Shows result in 3 hours
• It kills all types of weeds from the root
• Replacement policy
• No-mix formula
• Rainproof in 10 minutes
• You can use it around vegetables, mulched beds, patios, etc.
• Pump n go style.

This liquid kills the plants effectively enough. I had to take out a whole section of overzealous weeds in a raised bed, and it took two rounds of spraying a day, and it killed all the weeds! There were too many to pull up, so this was convenient.

The application of this weed killer is smooth and easy. Since the spray is battery operated and batteries are provided with the spray, it makes the whole process much quicker and hassle-free. Since it is ready to use, I could use it right out of the box. 

Also, this spray is super fast. After you have sprayed it on the weeds, you will see them die down within a day.

I have noticed that it does its job even faster when spread on a hot, dry day. I suggest keeping it away from the grass you don’t want dead.

However, one problem with this was that the tubing was kinked from inside the handle, and I had to pull the white tubing out enough to lessen the kink.

Pros

• Shows results in approximately 3 hours
• The weed killer can kill all types of weeds from the root
• It has no mixed ingredients or any sort of mixed formula
• Can easily be used around vegetables, mulched beds, and patios without getting them damaged
• The application is quite smooth and easy
• The spray is battery-operated and batteries are provided with the spray making it easy to spray on the grass and saving a lot of time
• It is a ready-to-use product
• The spray acts fast in killing all the weeds
• It works even faster when it is sprayed on a hot humid weather
• The weed killer has a pump-and-go mechanism
• Requires only 2 rounds a day
• The product has a policy where it can be replaced
• The weed killer is rainproof within 10 minutes of being used

Cons

• The product had tubing from inside the handle and the white tubing required it to be pulled to lessen the kink
• It can damage the grass

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2. Gordon’s SpeedZone Lawn Weed Killer

• Visible results within hours
• It Covers 14000 to 18000 square feet
• Works for common and troublesome weed species
• Cool-weather performance

The best part about this weed killer is that it targets all kinds of common and rare weeds.

It gets them to all and that too, quickly. I tried applying other herbicides, but some weeds were always left behind, but not with this one.

Also, this formula solved the issue of an infestation of sticker burs that plagued us.

They were all over the house and were too many to pull out, but this weed killer got rid of them as well. 

Moreover, this weed killer gets the job done without harming your grass!

This year, I had creeping Charlie, clovers, and wild violets in my yard, and after two applications, I was pleased to find that the weed was gone, but my grass was still the same.

However, one issue with it is that although it works effectively, sometimes it takes weeks to show accurate results, so you need to stay patient.

Pros

• The product shows visible results within a certain amount of hours
• Can easily cover around 18000 square feet which makes it quite feasible
• It proved to be efficient against common, rare, and troublesome weed species
• It works quite effectively against all kinds of weeds
• The mechanism works quickly and leaves no weed undamaged
• The weed killer has a cool-weather performance
• It even works well against infestation of sticker burs
• The weed killer makes sure that it works efficiently against only the weed that is harming the grass and doesn’t damage the grass at all
• The application was quite smooth

Cons

• It works effectively and quickly, however, sometimes it might take weeks to show results

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3. Natural Armor Weed and Grass Killer

This natural armor weed killer is one of its kind. The all-natural concentrated formula is highly in demand and for all the right reasons. Let’s see its features:

• Contains no glyphosate
• Effective for 250+ types of weeds
• No mixing or diluting required
• It can be used at all places where vegetation is not needed
• Fast results
• 30-days money-back guarantee

I am troubled by the hefty smell that comes after the weed killer is applied, but this weed killer had a pleasant after-smell that didn’t get too much into my head. Thus, it made the application a bit breezy.

Also, I lived in a desert community, and we recently had a lot of rain, thus creating a weed problem.

Some weeds were more troublesome than others, and I did not expect them to be gone so soon, but within hours, they vanished! 

Moreover, my item was well packaged. With other sprays, I noticed that there were mostly some leakages when they were delivered, but this one was appropriately packed, and I could use it immediately. 

However, note that the after-sale service is not up to the mark. I called them twice regarding an issue, and they took a week to get back to me.

Pros

• The weed killer works effectively against a variety of weeds that damage your grass – it is effective against 250+ types of weeds
• The weed killer requires no kind of mixing or diluting with any other product or substance
• The results are quick and visible
• The weed killer can be used in all kinds of places where vegetation is not involved
• The product has a policy of 30 days money back guarantee
• Not only is it efficient, but the weed killer has a pleasant smell after it is used
• The weed killer works efficiently even in harsh weather conditions and gives solid results within a few hours
• The product is well packed and has no sort of leakages as seen in other products
• Application was quite easy and caused no trouble
• Can be used right out of the box

Cons

• The after-sale customer service is not cooperative at all
• The customer service responds late

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4. Spectracide 96451 HG-96451 Weed & Grass Killer

• Volume is 64 fluid ounces 
• Results visible in 3 hours
• It kills the weed from the root
• Works for weeds on driveways, trees, flower beds, etc
• Mix and apply with a tank sprayer
• Money=back guarantee

I used 7 ounces per gallon of water, waited 24 hours to see the weed die, and it will take up to 2 days for the weed to properly pass. It works slower in shady areas, so it might take extra days in such areas. The results do start to show!

I have successfully killed the toughest weeds, including buttonweed, goosegrass, and spotted spurge.

It would help if you spotted spraying these weeds as this weed killer will kill anything it touches, and you don’t want your entire yard ruined.

Moreover, as someone who lives in an area that receives heavy and regular rainfall, this product becomes more suitable.

It becomes rainproof in just 15 minutes, so I don’t have to wait for a sunny and dry day to apply it.

One trouble that I faced with this product is that the instructions are a bit misleading and confusing. However, the product works just fine.

Pros

• The results of the weed killer are visible within 3 hours
• The product kills the weed from the root to the ground up
• The product has a policy of money back guarantee
• The product is feasible against weeds on driveways, trees, and flower beds
• Works well against the toughest species of weeds such as buttonweed, goosegrass, and spotted spurge
• The weed killer is quite strong and can kill any weed that it comes in contact with within a short period
• The product becomes rainproof within 15 minutes

Cons

• The instructions that come with the weed killer are misleading and confusing for the customer
• The weed killer must be used with extra care as it damages any grass that it comes in contact with
• It has to be mixed with water and requires extra time and effort in shady areas for it to show any results

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5. Southern Ag Atrazine St. Augustine Grass Weed Killer

• Kills broadleaf weeds
• You can use it in centipede grass
• Provides suppression of grass
• Controls weed from seeds and emerged weeds

Earlier this year, I noticed that crabgrass was taking over my St Augustin grass, and I found out that atrazine worked well with controlling crabgrass weed. Just know that atrazine is more effective in the spring and fall seasons.

One thing to be noted is that this weed killer takes a while to show results, so you have to remain patient.

I was getting worried after a week, but after three weeks, the weed did die down and made a significant improvement in my grass.

I used 5 ounces of surfactant and two-quarters of atrazine mixed into 5 gallons of water and applied it to approximately 7500 square feet. It worked well, and I could apply it in a short period.

One slight problem with the product is that it is more expensive than the rest, but the results make it worth it.

Pros

• Can be used not only for St Augustin grass but can also be used for centipede grass
• The weed killer can kill broadleaf weeds
• It can easily provide suppression of grass
• The weed killer can control crabgrass weed and works effectively in the spring and fall seasons
• The application is smooth
• The weed killer can be applied easily in a short period
• The product can cover around 7500 square feet of ground

Cons

• It takes weeks to show visible results, however, works like a charm against weed species
• It needs to be mixed with other products and substances to work effectively
• The product is expensive compared to other products, however, its results are worth making the purchase

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6. Scotts Liquid Turf Builder with Plus 2 Weed Control

Scotts is a brand known for yard products and taking care of your garden needs. Following are the main characteristics of the product:

• Volume is 32 oz
• Shows result in 24 hours
• It kills chickweed, ground ivy, henbit, among other weeds
• Attach hose and spray
• Don’t spray on flower beds, around trees or shrubs
• Spray when weeds are actively growing

The key to effectively using this product is to water your lawn 20 minutes before spraying this weed killer. If you follow these directions, you’ll notice that it kills almost all weeds and keeps the grass green and healthy.

Also, after application, I noticed that it only killed the weeds and not the healthy grass, which is a great plus. There is mostly a spillover of the product on healthy grass, and they get destroyed in the process.

It not only targets weed only, but it accelerates the growth of the grass too, too quickly! Also, since it is a spray, it is highly convenient to use; just keep an eye out on the liquid level and follow instructions.

One drawback of this product is that the bottle sometimes does not spray well and gets stuck. However, the product is not faulty.

Pros

• The weed killer shows results within 24 hours of it being used
• Can kill a variety of weeds such as Chickweed, ground ivy, and henbit
• It has an attached hose and spray mechanism
• The weed killer also makes the grass look green and healthy
• It only kills the weeds that are damaging the grass
• Volume is 32 fluid ounces
• The weed killer is not only effective in killing weeds, but it also acts as a catalyst since it accelerates the growth of grass
• It has a spray mechanism which makes it easy to use, even for a beginner
• It comes with well-detailed instructions

Cons

• Do not spray it on flower beds, trees, or shrubs since it can leave a negative effect on them
• Should only be sprayed if there are actively growing weeds
• The bottle sometimes gets stuck

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7. Ortho WeedClear Lawn Weed Killer Ready to Spray

• Volume is 32 fluid ounces
• Kills all main broadleaf weeds, including dandelion and chickweed
• Deliver results in hours
• Rainproof within an hour
• Suitable for multiple types of laws, including bermudagrass, tall fescue, etc.
• Treats up to 5000 square feet

The battery-powered sprayer it comes with makes life a lot easier. You can just grab the bottle and walk around the lawn to spot-treat the tough weeds without having to mix and pump a sprayer.

I lost most of my lawn to weeds after going organic for a couple of years.

Since it is a contract killer, most of my grass was intact even after I had sprayed them with it. This weed killer took some weeks, but the weed died.

Also, I would like to suggest adding some surfactant solution to the product as it helps the liquid stick on the weed, rather than running off them like water. I believe it quickened the process of weed dying.

However, one issue I faced was that it does not work well on dandelions, so you might want to reconsider if you plan to use it for that.

Pros

• Volume is 32 ounces
• Can kill all main broadleaf weeds including dandelion and chickweed
• Visible results within hours
• The product is rainproof within an hour of being used
• Covers an area of 5000 square feet
• The product is suitable for multiple lawns such as bermudagrass and tall fescue
• Comes with a battery-powered sprayer
• Kills the weed only and doesn’t affect the grass

Cons

• Requires an extra solution to be mixed with to get optimal performance
• Sometimes, the product can take weeks
• It does not work against dandelions

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8. Hi-Yield Atrazine Weed Killer

Atrazine’s weed killer has excellent reviews, to begin with, and is a lasting product. Listed below are some of its features:

• Volume is 32 fluid ounces
• Made in China
• Concentrated

Where I live, there is a specific type of weed called burweed that grows unnoticeably and is like carpet grass, so it doesn’t grow too much.

The problem is that you can’t catch it in the initial stages. I could kill all of it with this weed killer when I did. It did a fantastic job!

It not only kills the existing weed but also prevents new weed from growing! I roamed around my lawn months after applying this product, and there was no sign of burweed anywhere.

One important tip is to follow the instructions word by word! It is only to be used twice a year, the temperature has to be greater than 90F, and the lawn has to be watered three days after applying the product. 

One issue that I noticed is that it sometimes kills some of the grass when there is a significant spillover.

Pros

• It has a volume of 32 ounces
• The weed killer works efficiently against burweed which is similar to carpet grass and is undetectable
• It kills existing weeds and prevents other weeds from growing
• The instructions are quite helpful for beginners
• The application is smooth and requires to only be used 2 times a year
• It is concentrated and made in china

Cons

• It kills some of the grass if there is a spillover
• An optimal temperature is required for the weed killer to be effective
• The lawn has to be watered 3 days after the weed killer is used

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9. Scotts WeedEx Southern – 4,000 sq. ft., Weed Control

• Suitable for southern grasses, including st Augustin grass, centipede grass, and carpet grass
• Works in all seasons
• Watering immediately post-application
• It covers 4000 square feet

I put it on my st Augustin grass three weeks ago and finally saw the difference. The weeds are disappearing, and the grass is getting darker in the shade of green. When the rain stops, I’ll cut it out.

Also, the product is not very heavy on the pocket. The price is not unreasonable with the amount of area this bottle covers.

Since the price was competitive, I ordered two bottles and am still using them.

Moreover, the fact that it works in all seasons makes it all the more convenient.

Some weed killers are only suitable in certain weather conditions, but you can use this one at any time of the year.

However, the issue is that it does not work as well on bermudagrass as it does on st Augustin, and this is not mentioned on the product.

Pros

• The weed killer works in all seasons
• Can cover up to 4000 square feet
• It is suitable for all southern grass such as St Augustin grass, centipede grass, and carpet grass
• The weed killer not only kills the weed, but it also makes the grass darker and healthy
• The product is not heavy and can be carried easily
• The weed killer is suitable for the whole year instead of it being for a certain season
• According to the quantity of the product, the price is reasonable

Cons

• The product doesn’t mention that it works best for St Augustin grass, but not for bermudagrass
• The grass has to be watered after the application is used

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10. Ortho 0430005 B Gon Weed Killer for Lawns

• Volume is 128 fluid ounces
• It kills all kinds of broadleaf weeds
• Effective on 250+ types of weeds
• Results visible within hours

I had patchy yellow grass for months, and I finally decided to remove all the weeds and make my yard beautiful again.

Considering the cost of this weed killer, I’d consider it a wise move to use this as. Eventually, all the weed disappeared.

Also, this is the kind of weed killer that leads to a slow but sure death of weeds compared to an instant one. It does not kill them right away but kills every weed present in your grass.

Moreover, this product is excellent for significant areas. I had a 1-acre lawn, and to maintain that, I always struggled.

This product took care of everything; It not only killed weeds but prevented the emergence of new ones as well.

However, you should note that it is not recommended for chickweed as it is not as effective on them as on other kinds of weeds.

Pros

• Volume is 128 fluid ounces
• The weed killer can kill all kinds of broadleaf weeds
• Can kill a variety of weeds including 250+ types of weeds
• The results are visible within hours
• The price is reasonable
• Suitable for larger areas

Cons

• Not recommended for chickweed
• Takes some time to kill the weeds

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Factors to consider before buying:

• It is crucial to see that the product you use only kills the weed and not your grass, defeating the entire purpose. Herbicides, for example, will not kill your grass.
• Type of weed: Before you purchase the weed killer, inspect your garden, and try to find out the kind of weed you have since different products specialize in various types of weeds.
• Coverage: Some weed killers are diluted and won’t cover a large area, so it is highly recommended that you consider the size of the site you wish to use your product. Concentrated weed killers cover larger areas relatively. 

Buying Guide Weed Killer for St Augustin Grass

When it comes to front yards, grasses are an important aspect and it is your job to make them look as beautiful as they can be. However, maintaining thicker and greener grass requires a lot of time, effort, and energy.

St Augustin grass is the best warm-season turf grass that makes your lawn look nice and beautiful, however, to maintain its robust growth, you must pay close attention to it. Although St Augustin Grass is considered a thick beautiful grass, it is prone to weed and can damage the grass to the core.

I would recommend using Weed Killers so that the grass in your lawn has an ideal environment. Weed Killers play a vital role in providing St Augustin Grass with a secure environment and making sure that the grass isn’t invaded by weeds.

However, I would highly advise considering certain factors of Weed Killers before making the purchase.

The factors involving weed killers aren’t plenty, making it easier for a person such as myself to make a solid purchase.

Purpose

I would recommend identifying the sole purpose of the weed killer that you are planning to buy. The purpose of a weed killer is to simply eliminate the weed that is damaging the grass growing in your lawn.

However, I came across some weed killers that not only kill the weeds, but they damage the grass as well, defeating the whole purpose of a weed killer.

Type of weed

If you are a beginner such as myself, I would highly advise investigating the type of garden and the type of weeds that are attacking your lawn. The reason behind this is that many products specialize in different species of weeds.

If you don’t want to make an incorrect purchase, I would highly recommend inspecting your lawn, the grass growing, and the weeds attacking your lawn.

Coverage

Measuring the coverage of your lawn is crucial. I would advise buying weed killers that are suitable for the area of your lawn. If you have an average-sized lawn, I would recommend buying diluted weed killers since they are less concentrated and are highly efficient for smaller areas.

If you own a larger lawn such as myself, I would recommend buying concentrated weed killers since they can easily cover larger areas and are highly efficient in killing weeds in a shorter period.

Before making your purchase, I would advise investigating the measurements of your lawn since it would help you make a feasible decision.

FAQs

Can I use weed killer on St Augustin Grass?

St Augustin along with centipede grass plays a vital role in making your lawn look beautiful. However, they are sensitive to certain chemicals that are found in herbicides. To prevent any damage to the grass by using these herbicides, it is preferable to use Weed Killers to kill a variety of weeds that are damaging your lawn

Can you put weed killer over grass?

Your lawn is in danger if you apply weed killers to it within six months of the lawn being sowed. The weed killer instead of killing the weeds then damages the lawn. To prevent such damage, it is favorable to use weed killers which have Fluroxypyr as one of the ingredients. The products that have Fluroxypyr can be used within 2 months of the lawn being sowed

What are the most difficult weeds to control?

There are a variety of weeds that attack your lawn every day. Some of them can be eliminated using Weed Killers, but there are certain weeds that are quite difficult to control.

Field Bindweed, Ground ivy, Poison Ivy, Mugwort, and Burdock are some weeds that require extra attention. It is favorable that you investigate the type of weed attacking your lawn before making your purchase.

What is the best time to apply weed killer?

It is preferable to apply weed killers in spring. The reason behind this is that the weeds are in their pre-growth session during this time. However, the most effective season is considered the fall.

What is the best time of the day to use weed killer?

Weed killers should be used early in the morning so that they can have an effective impact on the weeds damaging your grass.