8 Best Weed killers For St Augustine Grass

8 Best Weed killers For St Augustine Grass

Weed and stickers is no less than a nightmare for gardeners and lawn owners. Their presence affect the development of grass shoots and potentially hampers their growth and appearance. That’s why getting rid of weeds and stickers as soon as possible is very important. There are various ways in which you can get rid of them and one of them is using weed killers.

Depending upon the size of your lawn you can decide which killer to buy for example for larger area you there are weed killers specifically designed for larger areas. St Augustine Grass is one such renowned lawn grass species. It is popularly cultivated for lush green meadows and commercial landscapes. This grass has praiseworthy benefits, making it a top choice for decorating your lawn with bright green carpets.

St Augustine grass has a thick and long texture. It gives a luxurious and dense look to your green space with broad and verdant grass blades. It is a warm-season grass growing mostly in Floria, Texas, and other southern parts of the United States. Due to its bushy turf growth, this grass is naturally weed-resistant. It minimizes weeds taking up any space between its roots.

Unfortunately, despite deterring weed, your st Augustine grass can get exposed to unwanted weed build-up.
You can clear out these weeds by using the best weed killers for st Augustine’s lawn. Highly synthetic or chemical weed killers can burn out your grass. Hang on with us to discover the best weed and feed for st Augustine grass.

What Types Of Weeds Are In St. Augustine grass?

What Types Of Weeds Are In St. Augustine grass?

Weeds have many faces. They may look like normal green plants which easily camouflage within your dense grass coat, but the shape and texture are recognizable.

Weeds also have particular seasons for appearing and vanishing as well. The type of weed growing in your lawn also highlights your soil type and lawn health. This acts as a major factor in deciding the best weed killer for St Augustine grass.
The most common weeds that target St Augustine grass are:

  • Dollar Weed
  • Bermuda grass
  • Poa Annua
  • Dallis grass
  • Henbit
  • Crabgrass
  • Clover
  • Chickweed

These weeds occasionally show up and spread over your magnificent St Augustine grass. Without further ado, let’s right away see some tried and tested best weed killers for st Augustine grass.

Best Weed Killer For St Augustine Grass

No beating around the bush! Let’s get down to the business. We have briefly explained all top herbicides for St Augustine grass, inclusive of its plus points and drawbacks. Rip that weed off your St Augustine lawn.

1. Scott’s Turf Builder Weed killer

Scotts is highest rated lawncare brand that manufactures a popular range of herbicides for killing weeds. Firstly, This weed killer comprises atrazine, which is a vital herbicide present in any best weed killer for st Augustine grass.

It effectively kills weeds without harming the grass’s health. Atrazine wipes out most types of weeds, including stubborn clover and dollar weeds. Further, it also works as a pre-emergent by preventing the birth of new weeds by feeding the grass blades.

On top of that, this herbicide for st Augustine grass is not just limited to a single purpose; it simultaneously nourishes and strengthens your grassroots so that they withstand hot temperatures and scarce water conditions.

It is tailor-made for Florida grass species and other southern areas. It comes in a standard formulation as well. The NPK (Nitrogen, Phosphorous, Potassium)ratio of Scott turf builder is 29:0:10. The high quantity of nitrogen accelerates plant growth and enhances greenery.

Potassium builds a strong immune system of the grass against diseases. This weed killer has a granule structure which can be easily spread over the lawn. After evenly distributing the weed killer, flush out your lawn with water to initiate the herbicide absorption process into the soil. This is the most important step for using weed killers.


  • Effective atrazine composition
  • Two-fold advantage of killing weeds and nurturing grass
  • Feasible and budget friendly
  • Usable both as a pre-emergent and post-emergent weed killer
  • Abundant nitrogen and potassium for lush green and well-maintained lawns.
  • Floratam friendly


  • Some weeds may escape and continue to grow even after using this weed killer.

2. Southern Ag 006130 Atrazine St. Augustine Weed Killer

One of Gardeners’ favorite best weed killers for Augustine grass. It has an atrazine formulation that works like a magic cleaner on nasty weeds without harming the St Augustine turf.

This liquid weed killer is customized specially to treat southern lawns and grass species. It has dual pre-emergent and post-emergent properties, which makes it a very desirable choice.

It effectively kills the ingrown weeds in the lawn and also destroys the novel budding weeds from their roots. By this, it serves the purpose of stopping new weeds from germinating and making a home between your grass carpet.

The area coverage for this weed killer goes up to 3720 sq. feet. For application, it cannot be sprayed directly. The liquid weed killer is very concentrated, and direct contact might harm your turf rather than killing weeds.

Always dilute the liquid herbicide with water and then spread it uniformly on your lawn or particular target spots. The only drawback is the high chemical content in this herbicide which can create unfavorable effects on your family and pets.


  • Fulfils Pre-emergent and post-emergent needs
  • Destroys not only upper-level weeds but also the roots
  • Value for money
  • It can cover 14000 sq. feet of area in just one gallon of product


  • High doses of chemicals can prove to be hazardous

3. Natural Armor Weed and Grass Killer

Hands down, this is the best natural weed killer for St Augustine grass. It is prepared from natural and environmentally friendly ingredients which are safe for your family and pets. It contains zero percent Glyphosate.

Along with being green, it provides fast action and visible results within hours. It puts an end to 250 varieties of weeds effectively. This liquid weed killer is concentrated with anti-weed agents, which act beneficially on weeds.

There’s no rocket science in using this best herbicide for st Augustine grass. Simply attach the spray valve, aim at the areas you wish to wipe out unwanted weeds, and just spray the mixture evenly.

There is no hassle of mixing or diluting the liquid. It is ideal to spray this on a sun-kissed day with at least 65°F temperature. Make sure there are no rain forecasts. After applying, you will see the weeds disappearing within 24 hours; that’s the speed and effectiveness of this best weed killer.

You can use this weed killer in any location where you don’t wish for any unpleasant vegetation, like near flowerbeds, fruit and vegetable gardens, lawns, Pools, walk stones, fence edges, and so on. You get all one advantage in a single weed killer.


  • Ease of use without any messy mixing
  • Multipurpose weed killer in all areas
  • 24-hour outcome with quick effect
  • Planet-friendly and contains no harmful chemicals like glyphosate
  • Safe for pets and kids


  • The sprayer can malfunction and leak the weed killer from the bottle
  • The effect of the liquid may not be long lasting

4. Roundup weed killer for Lawns

Round Up weed killers is one of the best weed killers for St Augustin grass which is designed specifically for southern grass lawns. It acts dominantly on stubborn weeds and finishes them off from their roots for complete removal.

It gets rid of the most common weed species like clover, dollar weed, dandelion, and over 93 types of weed. The liquid composition does not harm your grass or plants. It only targets unwanted greens.

This weed killer is really effective as it guarantees to kill the roots of the weeds so that they do not regrow. The ready-to-spray mechanism allows easy application across the grass and aids in the spot treatment of weeds.

It provides an area coverage of 6000 sq. feet. On top of that, it is rainproof for about 4 hours which shields the liquid from diluting in the rain. This weed killer comes in various packaging and properties, such as ready-to-spray, concentrated, and ready-to-use refills.

It also has a policy of replacement or money back if the product fails to satisfy the consumer. Be cautious, as this weed killer contains toxic chemical content, which can cause ill effects on pets and children. Keep them away while using the weed killer. Read the directions for use before applying it over your lawn for safety.


  • Fast Kill on contact action
  • Root targeting, which prohibits renewal
  • No harm to St Augustin grass turf
  • Safe and suitable for all southern lawns, including delicate centipede and Floratam
  • Simple spray application to cover maximum area at once


  • High amount of harmful chemicals noxious for children, pet dogs, cats, etc.

5. The Andersons Barricade Professional-Grade

Here, we have the top quality, granular, best pre-emergent weed killer for St Augustine grass. The granules are small-sized to provide more particle coverage per square inch. It contains prodiamine, an active herbicide that finishes 30 species of weeds, including henbit, crabgrass, foxtail, and much more.

It is a trustworthy weed killer which effectively prevents frequent growth and seasonal mushrooming of weeds all year long.

Coming to its magic mechanism, this weed killer has innovated with The Anderson’s patented Dispersible Granular (DG) Technology which enables the small granules to break down into thousands of microparticles on water contact.

This allows the absorption of herbicide into the deep soil layers, where it defends weed seed germination and prevents any further development of weeds. Being a pre-emergent, the timing of using the weed killer matter critically. It is crucial to understand that this weed killer will only prevent upcoming new weeds and not eradicate the existing weeds from your lawns.

For St Augustine grass, apply this weed killer in the early spring season before the 4-inch-deep soil heat onsets at 55 degrees Fahrenheit to prevent the germination of annual summer weeds. Further, you can apply it again in the mid-fall or autumn season to discourage the growth of winter weeds in southern lawns.

Irrigate the lawn after spreading granules for activating the dispersible herbicide. Note: If you have fostered new seeds, wait for 60 days or a second mowing session before using the weed killer else. It might backfire and deactivate your grass seeds instead.


  • Cost-effective for large lawns
  • Area coverage up to 12880 sq. feet with 40 lbs of weed killer
  • Two applications are enough to keep weeds away from your lawn
  • Effective Andersons patented Dispersible Granular (DG) Technology which travels down the soil to kill each early-stage weed.
  • Small granules allow wide coverage by every inch


  • Only applicable in two seasons
  • Might kill your new grass seeds if the timing is not appropriate.

6. Spectracide Weed killer

Another Atrazine powered the best herbicide for st Augustine grass. This excellent weed killer gives two benefits – a pre-emergent and a post-emergent liquid.

It kills the existing weeds from the lawn without harming your turf. Along with this, its on-contact action reaches within the soil to clear out weed seeds and also destroy weed roots completely.

In short, it gives total weed control to you with just a simple spray-on system. Atrazine works like a charm for eliminating unpleasant weeds and budding weed buds underneath the soil.

The quick flip hose end flip attaches easily to your garden hose for providing a uniform spread on the lawn. It is ideal for 3720 sq. feet of area. This weed killer is ready to spray and use in all seasons where the temperature is below 90 degrees Fahrenheit. Do not use it during high-temperature hours.


  • Presence of powerful atrazine
  • Easy set-up and application
  • Special southern grass formulation
  • Pre-emergent and post-emergent utility.


  • Time-taking process

7. Ortho Weed B Gon Weed Killer

Ortho weed B Gon killer is an easy and convenient spray-on herbicide that easily attaches to your garden hose. It is one of the best weed killers for St Augustine grass, including Floratam.

There is hardly any weed this weed killer spares. It can combat 250+ varieties of obstinate weeds found in different lawns and grass types. The weeds are wiped out not just externally but from deep roots to effectively stop their future visit.

If used properly by following the given directions, this weed killer is safe for your grass. There is no aftermath on the quality of grass. Do not expect to see results within hours of application. It takes 5 – 7 days for the herbicide to kill weeds and produce the desired outcome.


  • Kills 250 and above weed variety
  • Steady grip control and ready-to-spray action
  • Just needs 1 hour to be rainproof
  • Suitable even for Floratam (a hybrid of St Augustine grass)


  • Users report low power and unsatisfactory results
  • Weak built and packaging

8. Hi-Yield Atrazine Weed Killer

The last bestseller on the list is Hi-Yield Atrazine Weed killer, which is a pre-emergent as well as a post-emergent weed killer liquid. It comprises 4% atrazine which is a strong weed-deterring herbicide.

It is ideal for preventing Poa Annua, Henbit, and chickweed, which are found mostly in St Augustine grass and Centipede Grass Lawns. This dual-action weed killer successfully removes all unwelcome weed growths from roots within and also stops the germination of new weed seeds below the soil layers.

You accomplish two objectives at once, which saves time and ensures 100 percent weed deletion from the lawn for the present time and future both. A quarter of this weed-killer liquid can treat 3720 sq feet of area. All these features make this best weed killer for St Augustine grass competent in the market.


  • High atrazine content
  • No harm to grass blades
  • Rips off weed from roots
  • Restricts emergence of new weeds
  • You get value for money


  • Might cause discoloration on excessive use in one area.

How To Decide The Best Weed killer For St Augustine grass

We have seen the list of best weed killers for st Augustine grass. Now the question is which one to choose and how?
Weed killers are classified based on their purpose and core property.

It has two distinct uses, which bring us to two broad categories of weed killers: pre-emergent weed killers and post-Emergent weed killers. Your weed growth stage and situation will decide your choice of the best weed killer.

1. Pre- Emergent Weed Killer

Most people take action after the damage has been done. But if you are a cautious gardener and suspect any small weed growths in your lawn, you can begin early. Prevention is always better than cure. Pre-Emergent Weed killers are used to eliminate weed seeds that haven’t yet sprouted above the soil.

It forms a chemical layer below the soil and disrupts the germination stage of weeds, which stops their growth then and there at the earliest. It is usually applied over St Augustine grass during the late winter or early spring period when it’s dormant. Pre-emergent weed killers should be a part of your daily lawn care to keep the weeds at bay. Keep track of weed season and take steps accordingly.

2.  Post- Emergent Weed Killer

Post-emergent weed killers are used to treat existing weeds that are visible in patches between your bushes, flowers, and grass. They have a kill-on-contact property that allows the removal of weed growths from the lawn.

When you see weed sprouting in your lawn, use post-emergent and pre-emergent weed killers together to destroy mature weeds and prevent any further weed development from seeds. Best weed killers have both pre-emergent and post-emergent usage that takes care of all your worries single-handedly.


Weeds come to your lawn without an invitation, but you can choose to say goodbye to them. It’s just about finding the best weed killer for your St Augustine lawn that removes internal and external weed traces. Try finding an atrazine-rich weed killer, as it takes stronger action on hard weeds. With the use of a best weed spreader you would get more better results.

Stay up to date with your lawn care and begin the anti-weeding process at the perfect time to end on an expected note. Timing is very important for removing weeds fully from your lawn. Any amount of leftovers can cause a fresh wave of weeds yearly on your lawn.

Plan and use pre-emergent as well to avoid any future situations. Just follow the directions and tips, and you are good to go. Say Hello to beautiful, healthy lawns.


The best time to apply weed killer to St. Augustine grass is in the spring and fall seasons. The grass is not under stress when the weeds are actively growing season.

It is best to apply weed killer before mowing St. Augustine grass. Applying weed killer before mowing allows the herbicide to be absorbed more effectively by the weeds.

The time it takes for weed killer to work on St. Augustine grass will depend on the specific weed killer used. Generally, you can expect results of weed killer within 1-2 weeks.

Several natural weed killers are safe for use on St. Augustine grass, including weed killers containing vinegar, salt, and corn gluten meal.

It is generally recommended to wait at least 4-6 weeks after planting St. Augustine grass before applying weed killer. This allows the st. Agustine grass to establish a strong root system.

The frequency of weed-killer applications will depend on the severity of the weed problem. It is generally best to apply weed killer as needed to prevent the establishment of weeds in st. Agustine grass.

In most cases, applying a weed killer and fertilizer is not recommended at the same time, as this can increase the risk of damage to the grass. It is best to apply a weed killer and fertilizer separately.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *