Best Post Emergent Herbicide For St Augustine Grass

#1 · Best Overall

1. Southern Ag Atrazine Weed Killer

• Weight: 2.1 lb
• Form: Spray

Best for: St. Augustine Spot-Treatment Shoppers.

Why it ranks #1: Its listed use specifically names St. Augustine and centipede grass, and it controls emerged weeds and weeds from seed; one quart treats 3,720 square feet.

Coverage for 3,720 square feet per quart gives Southern Ag Atrazine a clear lawn-scale reference point, while its listed use on St. Augustine and centipede grass makes the intended turf fit explicit. It controls emerged weeds and weeds from seed, addressing more than weeds already visible.

The stated 4% atrazine content and control of many common grassy and broadleaf weeds give buyers a product aimed at multiple weed types rather than a single named target. Its use on St. Augustine and centipede lawns identifies where it is intended, and the quart coverage estimate helps plan treatment area. Because label instructions determine the application, users should follow the product directions rather than infer a mixing or application rate from the coverage figure alone.

Skip it if you need a fertilizer included with weed control; ferti-lome St. Augustine Weed & Feed 13917 combines herbicide with a 15-0-4 fertilizer mix.

A practical match for St. Augustine owners seeking control of both emerged weeds and weeds from seed, especially when the stated quart coverage suits the area. Follow the label for application directions and safety precautions.

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

#2 · Warm-Season Turf

2. Prime Source Celsius WG

• Weight: 18.14 g
• Form: Powder

Best for: Warm-Season Broad-Spectrum Control.

Why it ranks #2: The supplied description identifies post-emergent control for more than 120 weeds in warm-season turf, including St. Augustinegrass, making it a strong turf-specific alternative.

Three active ingredients give Celsius WG a broad-spectrum post-emergent approach, with the supplied description naming more than 120 annual and perennial broadleaf weeds and grasses. St. Augustine is among the warm-season turf types identified, making its stated turf fit especially relevant here.

Celsius WG is a foliar-applied powder, and the easy-mix packet provides a compact format for preparing a treatment. Its broad target range and explicit mention of St. Augustine grass make it relevant to buyers handling varied weeds in warm-season turf. The supplied listing does not provide a coverage figure or detailed application rate, so users need the product label to determine mixing and application for their lawn rather than extrapolate from packet weight.

Skip it if you need a listed coverage area before selecting a product; Southern Ag Atrazine 006130 states quart coverage of 3,720 square feet.

A relevant option for St. Augustine owners seeking broad post-emergent weed control in warm-season turf. Its easy-mix packet is compact, but the supplied listing lacks coverage details, so consult the label before planning treatment.

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

#3 · Larger Atrazine Size

3. Southern Ag Atrazine Gallon

• Weight: 4.3 oz
• Form: Spray

Best for: Larger St. Augustine Lawn Treatment.

Why it ranks #3: This larger Southern Ag atrazine option is listed for St. Augustine grass and controls emerged weeds, with broadleaf control and crabgrass suppression also described.

A one-gallon size sets this Southern Ag atrazine apart for buyers planning treatment beyond a small bottle, while its listed control of emerged weeds and weeds from seed addresses both visible and developing weed problems. The product is also identified for St. Augustine and centipede grass.

The listing describes control of many broadleaf weeds and suppression of crabgrass, giving the product more specific target information than a general lawn herbicide description. Its use on St. Augustine and centipede grass clarifies the stated turf fit. The one-gallon container is the supplied format, but no coverage figure is provided for this listing, so buyers should consult its label for application directions and the amount appropriate to their lawn.

Skip it if you need a stated coverage area to plan treatment; Southern Ag Atrazine 006130 specifies 3,720 square feet per quart.

A fit for St. Augustine owners seeking atrazine-based control of broadleaf weeds, emerged weeds, and crabgrass suppression in a one-gallon format. The listing gives no coverage figure, so use the label to plan application.

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

#4 · Weed-and-Feed Granules

4. Ferti-lome St. Augustine Weed & Feed

• Weight: 25.6 lb
• Form: Granules

Best for: Weed Control Plus Lawn Feeding.

Why it ranks #4: Formulated for St. Augustine and other listed warm-season lawns, it combines weed control with 15-0-4 fertilizer and covers 5,000 square feet.

A 15-0-4 fertilizer mix paired with pre- and post-emergent weed control lets ferti-lome St. Augustine Weed & Feed combine lawn feeding and weed management in one granular product. Its stated 5,000-square-foot coverage gives buyers a defined area for planning an early-spring application.

The fertilizer is intended for St. Augustine, centipede, and Zoysia lawns, while the product also controls weeds before and after emergence. That pairing suits buyers who want feeding and weed control in the same seasonal lawn-care step. The granule form and 5,000-square-foot coverage help with area-based planning, but the listing says application varies by footage and directs users to the label. It expressly excludes Bermuda and Northern grasses, so turf identification matters.

Skip it if you want a liquid concentrate for targeted weed treatment rather than granular weed-and-feed; Southern Ag Atrazine 006130 is listed as a spray.

Consider it if your St. Augustine lawn needs both weed control and fertilizer in an early-spring application. Avoid it on Bermuda or Northern grass, and use the label to determine the application for your lawn’s footage.

Listed on Amazon as: Fertilome (13917) St. Augustine Weed & Feed 15-0-4, 25.6 lbs

#5 · Sedge Specialist

5. Atticus Sertay Herbicide

• Weight: 1.25 oz
• Form: Water-Dispersible Granule

Best for: Southern Lawn Sedge Control.

Why it ranks #5: Its 75% sulfosulfuron formulation is described for warm-season turf and targets sedge, nutsedge, kyllinga, grassy weeds, and broadleaf weeds.

Sedge, nutsedge, and kyllinga control distinguishes Atticus Sertay from products focused only on broadleaf weeds. Its 75% sulfosulfuron formulation is described for warm-season turf, and the listing also names grassy and broadleaf weeds among its targets.

Sertay is a water-dispersible granule intended for young, actively growing weeds, with application listed for spring, summer, or fall. That seasonal flexibility and its target range can suit buyers facing sedge alongside other weeds in southern lawns. The supplied details identify warm-season turf but do not specifically name St. Augustine, so confirm the label’s turf directions and restrictions before use; follow its application instructions and aquatic-life caution.

Skip it if you need a listed St. Augustine fit rather than general warm-season turf language; Southern Ag Atrazine 006130 names St. Augustine directly.

A candidate for warm-season lawn owners targeting difficult sedge, nutsedge, or kyllinga alongside other weeds. Since the supplied facts do not specifically confirm St. Augustine use, verify turf compatibility and restrictions on the label.

Listed on Amazon as: Atticus Sertay Herbicide (1.25 oz) – Sulfosulfuron Selective Weed Control

#6

6. Nufarm Triplet SF

• Weight: 2 lb
• Form: Liquid

Best for: Broadleaf Control Across Turf Types.

Why it ranks #6: This post-emergent selective herbicide combines three herbicides for broadleaf weeds and is described for cool- or warm-season turf, though St. Augustine is not named.

Three selective herbicides form Nufarm Triplet SF’s approach to post-emergent broadleaf control, with the listing identifying use on both cool- and warm-season turf. Flexible application rates also let users select higher rates for problem areas and lower rates for turf maintenance.

Its selective, broadleaf-focused control makes Triplet SF a match for lawns where those weeds are the priority rather than a product described for every weed category. The warm-season turf listing is relevant to St. Augustine owners, while the adjustable application rates support different treatment contexts. The supplied facts do not explicitly name St. Augustine or provide coverage, so check the label for turf suitability, rate, and area before using it on that lawn.

Skip it if you want explicit St. Augustine labeling in the supplied facts; Envu Celsius WG names St. Augustine among its warm-season turf types.

A potential fit for buyers targeting broadleaf weeds across warm-season turf and wanting rate flexibility for problem areas or maintenance. Because St. Augustine is not explicitly named in the supplied facts, verify its label before use.

Listed on Amazon as: Nufarm Triplet SF Selective Herbicide, Post-Emergent Broadleaf Herbicide, 32 oz

#7

7. BASF Drive XLR8

• Weight: 4.2 lb
• Form: Liquid

Best for: Crabgrass and Residual Control.

Why it ranks #7: A post-emergent quinclorac concentrate targets crabgrass and other weeds, with up to 30 days of residual control; the supplied details do not name St. Augustine.

Up to 30 days of residual control gives BASF Drive XLR8 a defined weed-management window, while rainfastness in less than an hour can help limit weather-related disruption after application. Its water-based formulation is described as supporting faster plant uptake.

This liquid concentrate combines post-emergent control with broad-spectrum grassy and broadleaf weed targeting, making it relevant when visible weeds are the focus. The stated residual period may reduce the frequency of applications, while rainfastness in less than an hour offers a useful timing detail for planning around rain. The supplied facts do not confirm use on St. Augustine grass, so verify turf suitability and label directions before applying it to that lawn.

Skip it if you need a product listing explicit St. Augustine use; Southern Ag Atrazine 006130 names that turf type directly.

It may suit buyers prioritizing post-emergent grassy and broadleaf control with a stated residual period and quick rainfastness. For a St. Augustine lawn, the missing compatibility detail in the supplied facts makes label verification essential.

Listed on Amazon as: BASF Drive XLR8 Crabgrass Killer for Lawn & Turf, Post Emergent Grassy & Broadleaf Weed Control, Active Ingredient Quinclorac, 30 Day Residual, Herbicide, Concentrate 64 Ounce

#8

8. Atticus Torocity Mesotrione

• Weight: 8 oz
• Form: Liquid

Best for: Mesotrione Timing Flexibility Seekers.

Why it ranks #8: Its 40.0% mesotrione offers pre- and post-emergent activity against broadleaf and grassy weeds, but the supplied details do not establish St. Augustine compatibility.

Pre- and post-emergent activity is the defining advantage of Atticus Torocity: the mesotrione concentrate can address weeds before and after emergence, giving lawn-care planners more than one timing window. Its included pre-marked syringe also makes measuring the concentrate a more guided step.

Torocity contains 40.0% mesotrione, identified as the same active ingredient as Tenacity, and the listing describes use in newly seeded areas as well as established turf. That combination may suit buyers coordinating weed control with seeding, while the pre- and post-emergent activity offers timing flexibility. The supplied details do not establish St. Augustine compatibility, so buyers should verify the product label for their turf before use rather than assume it fits this lawn type.

Skip it if you need confirmed St. Augustine use from the listing; Southern Ag Atrazine 006130 explicitly names St. Augustine grass.

A candidate for buyers seeking mesotrione with both pre- and post-emergent activity and a measuring syringe. Its supplied facts do not confirm St. Augustine use, so check the label for turf compatibility before choosing it.

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

#9

9. The Andersons Meso 4 SC

• Form: Liquid

Best for: Seeding and Overseeding Plans.

Why it ranks #9: This mesotrione product controls more than 50 listed lawn weeds in pre- and post-emergent use, but the supplied information does not confirm St. Augustine suitability.

Compatibility with seeding and overseeding, except for fine fescue, is the key distinction of The Andersons Meso 4 SC. This mesotrione liquid offers both pre- and post-emergent weed control, letting buyers address existing weeds while planning new lawn growth.

The product controls more than 50 common broadleaf and grassy weeds, with named examples including clover, crabgrass, dandelion, foxtail, ground ivy, henbit, and nutsedge. Its pre-emergent use with grass seed blends and stated safety for seeding or overseeding can support a lawn-renewal workflow, except with fine fescue. The supplied details do not confirm St. Augustine compatibility, so verify the label for that turf before applying it.

Skip it if you need confirmed St. Augustine use; Southern Ag Atrazine 006130 explicitly lists St. Augustine and centipede lawns.

A useful candidate for lawn projects combining mesotrione weed control with seeding or overseeding, provided the grass is not fine fescue. St. Augustine compatibility is not confirmed in the supplied facts, so check its label first.

Listed on Amazon as: The Andersons Meso 4 SC – Mesotrione Pre-Emergent and Post-Emergent Weed Control 8 fl. oz.

#10

10. Liquid Harvest Mesotrione

• Weight: 8 oz
• Form: Liquid

Best for: Mesotrione Users Planning Watering.

Why it ranks #10: Its mesotrione targets 46 listed broadleaf and grassy weed species, but the supplied grass list does not establish St. Augustine compatibility.

A target list spanning 46 broadleaf species and grasses gives Liquid Harvest Mesotrione a defined breadth, including crabgrass, clover, chickweed, and dandelion. Its pre- and post-emergent activity lets buyers consider it for both weed prevention and weeds already present.

The product is a liquid mesotrione concentrate that the listing says begins absorbing upon application, although full weed death may take two to three weeks. Water activates it; if rainfall does not occur within 10 days, the directions specify applying 0.15 inches of water. Those timing and watering details matter for treatment planning. The supplied facts do not confirm St. Augustine compatibility, so verify the label for that turf before use.

Skip it if you need listed St. Augustine compatibility; Envu Celsius WG explicitly names St. Augustine among its warm-season turf types.

Consider it if you want mesotrione’s pre- and post-emergent activity and can plan around its water-activation directions. The supplied details do not verify St. Augustine use, so confirm the label before treating that grass.

Listed on Amazon as: Liquid Harvest Mesotrione – 8oz – Mesotrione Concentrate (Compare to Tenacity) – Pre and Post-Emergent Weed Killer for Lawn and Turf Grasses