Best Herbicides For St Augustine Grass: 10 Options Compared

#1 · Best Overall

1. Southern Ag Atrazine 32 oz

• Weight: 2.1 lb
• Form: Spray

Best for: St. Augustine And Centipede Lawns.

Why it ranks #1: Explicitly for St. Augustine and centipedegrass, it controls emerged weeds and weeds from seed; one quart treats 3,720 square feet.

Coverage of about 3,720 square feet per quart gives Southern Ag Atrazine a clear role for treating a substantial St. Augustine or centipede lawn. Its listed control includes emerged weeds and weeds from seed, so it can address visible growth as well as new weeds emerging in treated areas.

This spray contains 4% atrazine and is labeled for St. Augustine and centipede lawn grasses, matching the turf types named for this roundup. Control of many common grassy and broadleaf weeds gives it a wider target than a product aimed at one weed category. The stated one-quart coverage of 3,720 square feet helps with planning lawn treatment; follow the label’s application directions and safety information when using it.

Skip it if you want a ready-to-spray hose attachment; Ortho WeedClear connects directly to a garden hose.

Choose this Southern Ag concentrate if you need broad weed control across a St. Augustine or centipede lawn and can measure and apply a concentrate. Its listed coverage helps estimate treatment needs, but the label remains essential for rates and safe use.

Listed on Amazon as: Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz Specialty Herbicide, Light Tan

#2 · Best Weed List

2. Hi-Yield Atrazine 32 oz

• Weight: 2.2 lb
• Form: Liquid

Best for: Seasonal Atrazine Concentrate Users.

Why it ranks #2: For St. Augustine and centipedegrass, it lists control of henbit, dollarweed, chickweed, clover, and sandspur, with coverage up to 3,720 square feet.

Treatment coverage up to 3,720 square feet from a 32-ounce bottle gives Hi-Yield Atrazine a useful planning benchmark for St. Augustine lawns. It controls named weeds such as henbit, clover, chickweed, dollarweed, and sandspur, and can be applied during dormant or growing seasons.

This liquid concentrate is intended for St. Augustine and centipedegrass, with control of both emerged weeds and weeds from seed. Its listed coverage can help homeowners estimate how much lawn one bottle treats, while its seasonal use includes dormant and growing periods for established turf. Application requires shaking the bottle, diluting according to the label, and spreading evenly with a sprayer or watering can; early spring is identified for best results.

Skip it if you prefer a ready-to-spray product with no dilution step; Image Herbicide comes in a ready-to-spray format.

Choose Hi-Yield if you want a measured-coverage atrazine concentrate for established St. Augustine or centipedegrass and can mix and apply it evenly. Early spring is noted for best results, although use is listed for dormant and growing seasons.

Listed on Amazon as: Hi-Yield (33430) Atrazine Weed Killer, 32 oz

#3 · Best for Floratam

3. Image Weed Killer for Southern Lawns

• Weight: 2 lb
• Form: Liquid

Best for: Ready-To-Spray Southern Lawns.

Why it ranks #3: Designed for southern lawns and specifically Floratam, this ready-to-spray product targets tough broadleaf weeds and reports visible results in hours.

A ready-to-spray format makes Image Herbicide a practical option for St. Augustine lawn care without a concentrate-mixing step. The product specifically names Floratam lawns and promises visible results in hours, while targeting tough broadleaf weeds in southern grasses including St. Augustine.

Image’s sprayer format supports direct lawn application, and its instructions call for spraying evenly over the weeds. The stated fast action, with visible results in hours, gives buyers a clear indication of when changes may appear. It targets tough broadleaf weeds and is described as killing weeds down to the root; its southern-grass use includes St. Augustine, Bermuda, and Zoysia. Use only as directed, including the label’s precautions for people and pets.

Skip it if you want a stated lawn coverage area before buying; Hi-Yield Atrazine lists coverage up to 3,720 square feet.

Image fits homeowners seeking a ready-to-spray treatment for broadleaf weeds in St. Augustine, especially Floratam lawns. It also names Bermuda and Zoysia, but the supplied details give no coverage figure, so check the label when planning application.

Listed on Amazon as: Image Herbicide Weed Killer for Southern Lawns, 32 Oz

#4 · Best for Nutsedge

4. PBI-Gordon Aethon Nutsedge Killer

• Weight: 2.3 lb
• Form: Liquid

Best for: Nutsedge And Sedge Regrowth Control.

Why it ranks #4: Specifically lists St. Augustine and centipede lawns and targets yellow and purple nutsedge, annual sedge, and kyllinga with two active ingredients.

A dual-active formula aimed at underground reproductive structures distinguishes PBI-Gordon Aethon from leaf-focused nutsedge treatment. Its listed targets include yellow and purple nutsedge, annual sedge, and kyllinga rhizomes, with St. Augustine and centipede named among compatible lawns.

Aethon is a selective post-emergent liquid concentrate for warm-season turf, including St. Augustine and centipede. The listed blend contains penoxsulam at 1.24% and pyrimisulfan at 1.24%, and its product description says Vexis Technology reaches reproductive structures to break the regrowth cycle. That focus suits buyers dealing with sedges that return from below ground. The label advises against application when rain is expected within six hours and calls for cool, dry storage.

Skip it if you need broad control of common lawn weeds beyond sedges; Ortho WeedClear lists more than 250 common broadleaf weeds.

Aethon fits St. Augustine or centipede owners focused on nutsedge, annual sedge, or kyllinga regrowth from below ground. It is a selective post-emergent concentrate, and its rain restriction makes a suitable application window important.

Listed on Amazon as: PBI-Gordon Aethon Nutsedge Killer for Lawns, St. Augustine, Centipede, 1 Qt

#5 · Broadest Weed Range

5. Envu Celsius WG

• Weight: 18.14 g
• Form: Powder

Best for: Warm-Season Turf Broad-Spectrum Control.

Why it ranks #5: Its three-active-ingredient postemergent formula is described for warm-season turf, including St. Augustine, and controls more than 120 annual and perennial weeds.

Three active ingredients give Celsius WG a broad-spectrum postemergent role for warm-season turf, including St. Augustinegrass. The product description says it controls more than 120 annual and perennial broadleaf weeds and grasses, making it relevant when a lawn has varied weed targets.

Celsius WG is a foliar-applied postemergent herbicide, so its stated role is treating weeds after they are present rather than relying on a pre-emergent claim. Its three active ingredients support the listed broad spectrum across warm-season turf types, including St. Augustinegrass, Bermudagrass, and centipedegrass. This item is a powder supplied as an easy-mix packet, which makes packet preparation part of the workflow; follow the product label for mixing and application directions.

Skip it if you need a stated coverage figure for each packet; Bug And Blade Celsius WG lists treatment coverage up to 4,000 square feet.

Celsius WG suits buyers seeking postemergent control across warm-season turf with a broad mix of weed types. St. Augustinegrass is specifically included, but the supplied listing gives no packet coverage or rate, so use the label to plan treatment.

Listed on Amazon as: Prime Source Celsius WG – 0.226 oz Easy Mix Packet-Post Emerge Weed Control

#6

6. Southern Ag Atrazine 1 Gallon

• Weight: 4.3 oz
• Form: Spray

Best for: Gallon-Size Atrazine Lawn Treatment.

Why it ranks #6: The product is identified for St. Augustine and centipedegrass and claims broadleaf control, crabgrass suppression, and control of emerged weeds and weeds from seed.

A one-gallon container sets this Southern Ag Atrazine apart for lawn owners who want a larger supply of a St. Augustine grass herbicide. Its listed targets include broadleaf weeds, crabgrass suppression, emerged weeds, and weeds from seed, with centipede grass also named for use.

The spray is identified for St. Augustine grass and also for centipede grass, giving it a fit across those two warm-season lawn types. Its stated functions span killing many broadleaf weeds, suppressing crabgrass, and controlling emerged weeds and weeds from seed. The one-gallon size offers a larger supply than the brand’s quart listing, but the supplied information does not specify coverage or an application rate, so use the product label for treatment directions.

Skip it if you need a stated coverage figure for planning; Hi-Yield Atrazine lists treatment up to 3,720 square feet.

Consider this Southern Ag gallon if you want atrazine weed control for St. Augustine or centipede grass and value a larger container. Since no coverage figure is supplied here, it suits buyers prepared to rely on the product label for rates.

Listed on Amazon as: Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon

#7

7. Bug And Blade Celsius WG

• Weight: 12.75 g
• Form: Granule

Best for: Two-Treatment Seasonal Weed Program.

Why it ranks #7: The listing describes two treatments and claims control of 120-plus weeds, but the supplied details do not clearly establish St. Augustine compatibility.

Two packets and stated coverage up to 4,000 square feet let this Celsius WG bundle frame a spring-and-fall weed-control plan. Its description calls for one treatment as weeds emerge in early spring and another in late summer or fall, targeting more than 120 weeds.

Each packet is described as a two-gallon treatment, with two applications intended to span a warm-season lawn’s spring-through-dormancy cycle. The listing names crabgrass, dollarweed, and clover among more than 120 weeds, giving buyers concrete target examples. Celsius WG is the herbicide in the bundle, and its manufacturer is Envu; however, the supplied facts do not name St. Augustine specifically, so verify the label’s turf directions before applying it to that grass.

Skip it if you require an explicitly named St. Augustine product; Southern Ag Atrazine lists St. Augustine grass on its use directions.

This bundle fits buyers planning two seasonal applications and targeting listed weeds such as crabgrass, dollarweed, and clover. Because the supplied product facts do not identify St. Augustinegrass, confirm turf eligibility on the label before using it there.

Listed on Amazon as: Celsius WG Herbicide 2-Pack with Bug And Blade Weed ID Card

#8

8. Ortho WeedClear Ready-To-Spray

• Weight: 8 oz
• Form: Liquid

Best for: Hose-Connected Broadleaf Weed Control.

Why it ranks #8: Its ready-to-spray format and stated control of more than 250 broadleaf weeds are convenient, but the supplied details do not confirm St. Augustine use.

A garden-hose connection turns Ortho WeedClear Ready-To-Spray into a straightforward option for treating lawn weeds without a separate mixing step. It targets more than 250 common broadleaf weeds, with visible results in hours and a stated rainproof period after drying.

The sprayer attaches to a garden hose, and its switch starts application, simplifying the setup for homeowners treating small, actively growing weeds. The product is listed for lawn use and is described as killing broadleaf weeds down to the roots, including dandelions, clover, chickweed, and dollarweed. Its directions identify spring or fall use, and it becomes rainproof in one hour upon drying. Follow the label’s instructions for lawn and re-entry use.

Skip it if you need control of grassy weeds as well as broadleaf weeds; Celsius WG lists broadleaf weeds and grasses among its targets.

Ortho suits homeowners who want hose-connected application for common broadleaf weeds in lawns, especially when weeds are small and actively growing. Its stated rainproof timing is one hour after drying, so weather and drying conditions matter.

Listed on Amazon as: Ortho WeedClear Weed Killer for Lawns Ready-To-Spray, 32 fl. oz.

#9

9. Atticus Torocity Mesotrione

• Weight: 8 oz
• Form: Liquid

Best for: Pre- And Post-Emergent Mesotrione.

Why it ranks #9: Mesotrione provides pre- and post-emergent activity, but the supplied product details do not specifically confirm use on St. Augustine grass.

Pre- and post-emergent activity gives Atticus Torocity flexibility to address weeds before or after emergence. Its 40.0% mesotrione active ingredient is identified as the same active ingredient as Tenacity, and the supplied facts include an easy-measure pre-marked syringe.

Torocity is a liquid concentrate with both pre-emergent and post-emergent activity, allowing treatment timing to vary with whether weeds are emerging or already present. The description says it controls and prevents broadleaf and grassy weeds, while mesotrione is identified as its active ingredient at 40.0%. A pre-marked syringe supports measuring the concentrate, which can make dosing more manageable. The supplied facts do not name St. Augustinegrass specifically, so check the label for turf eligibility and directions.

Skip it if you need St. Augustinegrass named in the supplied use information; Southern Ag Atrazine explicitly lists that grass.

Torocity fits buyers seeking mesotrione with both pre- and post-emergent activity and a syringe for measuring concentrate. Its described targets include broadleaf and grassy weeds, but confirm St. Augustine eligibility and application directions on the label.

Listed on Amazon as: Atticus Torocity Mesotrione Herbicide (8oz) – (Compare to Tenacity)

#10

10. Syngenta Tenacity Turf Herbicide

• Weight: 8 oz
• Form: Liquid

Best for: Mesotrione Turf Treatment Planning.

Why it ranks #10: This mesotrione product is described for selective turf weed control, but the supplied listing does not establish St. Augustine compatibility.

Systemic pre-emergence and post-emergence action gives Syngenta Tenacity two timing roles for selective weed control in turfgrasses. Its listed targets include crabgrass, chickweed, clover, dandelion, yellow nutsedge, and more, while mesotrione makes up 40% of the active ingredient.

Tenacity’s pre-emergent use works as weeds absorb the product while emerging from soil; its post-emergent use adds a separate timing option for existing weeds. The supplied target list spans broadleaf and grassy weeds, including large and smooth crabgrass, foxtail, goosegrass, and clover. It is a liquid herbicide, but the supplied information does not identify St. Augustinegrass specifically or provide a rate, so check the label for turf suitability and application details.

Skip it if you want St. Augustine explicitly named in the product facts; Southern Ag Atrazine lists St. Augustine grass for use.

Tenacity suits buyers seeking mesotrione with both pre- and post-emergent roles and a broad listed target set. The supplied information does not specify St. Augustinegrass or an application rate, so verify turf directions before planning treatment.

Listed on Amazon as: Tenacity Turf Herbicide – 8 ounces (Packaging may vary)