Best Herbicide For St. Augustine Grass is essential for homeowners and turf managers who want a healthy, vibrant, and weed-free lawn. St. Augustine grass thrives in warm climates, providing dense green coverage, but it is highly susceptible to a variety of weeds that can ruin its appearance and compete for nutrients.

Weeds like crabgrass, nutsedge, and broadleaf species can quickly spread if left untreated, causing patchy growth and thinning turf. Proper weed control not only improves aesthetic appeal but also ensures your lawn maintains optimal health and resilience against environmental stressors.

Selecting the right herbicide requires understanding weed types, turf sensitivity, and application techniques. Lawn professionals recommend using selective herbicides that target specific weeds while protecting the grass from damage, which saves time and reduces long-term maintenance costs.

In this guide, we evaluate the best herbicide for St. Augustine grass, highlighting the most effective products, their applications, and key tips for optimal lawn care. By following these recommendations, you can achieve superior weed control and maintain a lush, healthy lawn year-round.

Related: Best Electric Lawn Mower For St Augustine Grass

10 Best Herbicide For St. Augustine Grass

1. Atrazine Turf Herbicide – Best Herbicide for Broadleaf and Grass Control

Atrazine Turf Herbicide provides both pre- and post-emergent control for broadleaf and grassy weeds in St. Augustine grass. Its active ingredient penetrates weed roots, effectively preventing regrowth and seed production. Additionally, Atrazine’s selective formula ensures minimal impact on the turf while controlling a wide spectrum of weeds.

Apply Atrazine during the early growth stage of weeds for optimal results. It becomes rainfast within six hours and maintains residual activity for weeks, making it perfect for lawns with recurring weed problems. Turf managers also note its cost-effectiveness compared to other dual-action herbicides.

Field studies demonstrate 85-90% control of weeds with Atrazine in St. Augustine lawns. Its ability to handle both grassy and broadleaf weeds simultaneously makes it a top choice for general weed management. Regular applications ensure dense, healthy turf without compromising its vibrant green color.

Pros:
• Dual-action
• Effective
• Residual control
• Cost-effective
• Selective
• Easy-apply
• Long-lasting

Cons:
• Sensitive plants
• Moderate odor
• Requires calibration

---

2. Image Kills Nutsedge Turf Herbicide – Best Herbicide for Nutsedge Control

Image Kills Nutsedge targets nutsedge and other challenging weeds without damaging St. Augustine grass. Its active ingredient, imazaquin, interferes with amino acid synthesis in weeds, effectively eliminating them. Moreover, its selective formulation ensures the grass remains healthy and vibrant.

For best results, apply during early weed growth and avoid dry, hot conditions. The herbicide integrates well with standard turf maintenance practices and can be tank-mixed with surfactants for improved absorption. Homeowners report faster visible results within days after application.

University trials show 90-95% nutsedge control when applied correctly. Its precision action makes it ideal for sensitive areas where turf damage must be minimized. Additionally, the product is safe for both residential and commercial landscapes.

Pros:
• Targeted control
• Selective
• Fast-acting
• Turf-safe
• Easy-apply
• Long-lasting
• Compatible

Cons:
• Limited use
• Sensitive to heat
• Pricey

---

3. Sedgehammer Turf Herbicide – Best Herbicide for Tough Nutsedge

Sedgehammer offers precise control of nutsedge without harming St. Augustine grass. Its active ingredient, halosulfuron-methyl, targets weeds at the root level, preventing regrowth. Furthermore, it is compatible with most turfgrass species, making it versatile for mixed lawns.

Apply Sedgehammer during early weed emergence for maximum efficacy. The product becomes rainfast within four hours, allowing flexible scheduling for lawn care professionals. Additionally, it requires a low use rate, reducing chemical exposure to the environment.

Field studies indicate 90% control of nutsedge using Sedgehammer. Its selective action ensures the surrounding turf remains healthy, making it a preferred choice for sensitive and high-traffic areas. With consistent application, lawns stay lush and weed-free.

Pros:
• Root-targeted
• Selective
• Low-use rate
• Turf-safe
• Flexible
• Quick-dry
• Reliable

Cons:
• Expensive
• Slow initial results
• Limited availability

---

4. Drive XLR8 Turf Herbicide – Best Herbicide for Crabgrass Control

Drive XLR8 effectively controls grassy weeds, including crabgrass, in St. Augustine lawns. Its active ingredient, quinclorac, attacks both the foliage and roots, ensuring complete weed elimination. Moreover, its selective formula protects desirable turf from damage.

The herbicide is rainfast within four hours, allowing for application during variable weather. It is also suitable for spot treatments or large-scale lawn care, providing flexibility. Additionally, homeowners note visible improvement within two weeks of treatment.

Field trials show 85-90% crabgrass control with Drive XLR8. Its dual-action properties and turf-safe profile make it a reliable choice for maintaining clean, dense St. Augustine grass. Regular monitoring ensures continued weed suppression.

Pros:
• Fast-acting
• Dual-action
• Selective
• Turf-safe
• Flexible
• Easy-apply
• Reliable

Cons:
• Sensitive to heat
• Moderate odor
• Needs monitoring

---

5. Tenacity Turf Herbicide – Best Herbicide for Broadleaf and Grass Management

Tenacity offers both pre- and post-emergent weed control in St. Augustine lawns. Its active ingredient, mesotrione, inhibits photosynthesis in weeds, causing them to turn white and die. Furthermore, Tenacity is highly effective against both broadleaf and grassy weeds.

Apply Tenacity during early weed growth for best results. Its rainfast properties within two hours ensure flexibility for lawn maintenance schedules. Additionally, it has low toxicity for the turf, reducing potential damage.

University trials demonstrate 90% weed control using Tenacity. Its dual-action formula and low use rate make it ideal for sensitive environments or high-traffic lawns. Consistent use maintains dense, green turf while suppressing future weed emergence.

Pros:
• Dual-action
• Effective
• Turf-safe
• Low-use rate
• Fast results
• Broad-spectrum
• Easy-apply

Cons:
• Expensive
• Short residual
• Limited availability

---

6. Specticle Turf Herbicide – Best Pre-Emergent for Weed Prevention

Specticle is a pre-emergent herbicide that prevents weed establishment in St. Augustine grass. Its active ingredient, indaziflam, inhibits root growth, stopping weeds before they emerge. Additionally, its long-lasting residual action ensures extended protection.

Apply Specticle before weeds germinate for maximum effectiveness. It is rainfast within two hours, allowing for flexible scheduling. Turf managers report up to 95% weed prevention in treated areas.

Its extended residual makes it ideal for areas prone to recurrent weed problems. Specticle also integrates well with standard lawn care practices. Using it early in the season reduces labor and chemical inputs later.

Pros:
• Pre-emergent
• Long-lasting
• Turf-safe
• Effective
• Flexible
• Easy-apply
• Reliable

Cons:
• Expensive
• Not post-emergent
• Limited availability

---

7. Revolver Turf Herbicide – Best Herbicide for Grassy Weed Control

Revolver targets grassy weeds effectively while preserving St. Augustine grass. Its active ingredient, foramsulfuron, attacks both roots and leaves, ensuring complete weed removal. Furthermore, its selective formula protects desirable turf from damage.

Apply Revolver during early weed growth stages for best results. Rainfast properties allow for flexible application timing. Additionally, it works well in both residential and commercial turf management.

Field trials indicate 85-90% control of grassy weeds. Its precision action and turf-safe profile make it a top choice for challenging lawn conditions. Proper application maintains healthy, dense grass throughout the season.

Pros:
• Root-targeted
• Fast-acting
• Selective
• Turf-safe
• Flexible
• Easy-apply
• Reliable

Cons:
• Expensive
• Slow initial results
• Limited availability

---

8. Certainty Turf Herbicide – Best Herbicide for Tough Grassy Weeds

Certainty is highly effective against hard-to-control grassy weeds in St. Augustine lawns. Its active ingredient, sulfosulfuron, disrupts weed growth at both the root and foliage levels. Additionally, it is safe for the turf, preventing damage during treatment.

For optimal performance, apply Certainty during early weed development. Rainfast within four hours, it integrates seamlessly with lawn maintenance schedules. Turf managers report significant weed reduction after just one application.

University trials show 85-90% control of tough grassy weeds. Its selective action and consistent performance make it ideal for professional and home applications. Regular monitoring ensures sustained weed-free turf.

Pros:
• Tough control
• Selective
• Turf-safe
• Fast-acting
• Effective
• Easy-apply
• Reliable

Cons:
• Expensive
• Sensitive to heat
• Limited supply

---

9. Dismiss Turf Herbicide – Best Herbicide for Broadleaf Weed Control

Dismiss provides effective control of broadleaf weeds in St. Augustine grass. Its active ingredient, sulfentrazone, targets both foliage and roots for complete elimination. Furthermore, it preserves turf health while suppressing weed regrowth.

Apply Dismiss during early weed growth for optimal results. Rainfast within two hours, it allows flexible scheduling. Lawn professionals recommend Dismiss for areas with persistent broadleaf infestations.

University studies show 90% weed control using Dismiss. Its selective action and proven effectiveness make it a top choice for both residential and commercial lawns. Regular applications maintain vibrant, dense turf throughout the season.

Pros:
• Broadleaf control
• Turf-safe
• Fast-acting
• Effective
• Easy-apply
• Reliable
• Flexible

Cons:
• Expensive
• Short residual
• Limited supply

---

10. Roundup Pro Max Turf Herbicide – Best Herbicide for Spot Treatment

Roundup Pro Max is a non-selective herbicide ideal for spot treatments of weeds in non-turf areas. Its active ingredient, glyphosate, destroys the entire plant, including roots. Additionally, it delivers fast results for localized weed problems.

Apply Roundup Pro Max carefully to avoid contact with desirable turf. Rainfast within two hours, it works effectively under most weather conditions. Homeowners appreciate its quick action for managing small infestations.

Field trials demonstrate 95% weed control with Roundup Pro Max. While non-selective, it is perfect for precise, targeted applications. Its effectiveness reduces repeated labor and maintains clean lawn edges.

Pros:
• Fast-acting
• Effective
• Root-targeted
• Reliable
• Easy-apply
• Spot treatment
• Quick results

Cons:
• Non-selective
• Requires care
• Limited turf use

---

Best Herbicide For St. Augustine Grass FAQs

1. What is the safest herbicide for St. Augustine grass?
   Selective herbicides like Atrazine, Tenacity, and Sedgehammer are safest for St. Augustine grass. Always follow label directions to avoid turf damage.
2. Can I use pre-emergent herbicides on existing weeds?
   Pre-emergent herbicides like Specticle prevent new weeds but do not kill existing ones. Post-emergent products are needed for active infestations.
3. How often should I apply herbicides on St. Augustine lawns?
   Application frequency depends on the weed type and product. Generally, follow label guidance and reapply as weeds re-emerge.
4. Are these herbicides safe for pets and children?
   Most selective herbicides are safe once dry. Always keep children and pets off treated areas until recommended waiting times have passed.
5. Can I mix herbicides for better control?
   Certain herbicides can be tank-mixed with surfactants for improved absorption. Always read labels for compatibility before combining.
6. What time of year is best for herbicide application?
   Early weed growth stages in spring or fall are optimal. Avoid extreme heat or drought conditions for best results.
7. How do I prevent herbicide resistance in St. Augustine grass?
   Rotate herbicides with different modes of action. This reduces the risk of weeds developing resistance over time.

---

Conclusion

In conclusion, the best herbicide for St. Augustine grass is Atrazine Turf Herbicide due to its dual-action formula, selective safety, and reliable control of broadleaf and grassy weeds. The runner-up is Tenacity Turf Herbicide because it offers excellent pre- and post-emergent action for sensitive turf environments.

Atrazine was selected as the best because it provides broad-spectrum control and long-lasting residual effects while maintaining turf health. Tenacity earns its runner-up position for its versatility and low-use rate, ideal for both residential and commercial lawns.

Each herbicide in this guide was chosen based on effectiveness, safety for St. Augustine grass, and ease of application. Using the right product ensures consistent turf density, vibrant color, and minimized weed regrowth.

Ultimately, investing in quality herbicides improves lawn appearance, reduces maintenance, and protects your turf investment. Take action today by selecting the right herbicide to maintain a lush, weed-free St. Augustine lawn year-round.