Finding the right herbicide for St. Augustine grass depends on weed type, turf health, and local climate. This guide compares five widely available products to help you choose the best fit for your yard. Each option is explained with who it’s best for, key considerations, and any limitations to watch for.
| Product | Best For | Key Benefit |
|---|---|---|
| Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz | St. Augustine and centipede lawns with broadleaf weed pressure | Strong broadleaf weed control per quart coverage (3,720 sq ft) |
| Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon | Areas with crabgrass suppression needs and multiple broadleaf weeds | Kills many broadleaf weeds and provides crabgrass suppression |
| PBI-Gordon Aethon Herbicide SL, 1 Quart | Floratam and other warm-season grasses facing tough weeds | High-spectrum weed control with underground tuber suppression |
| St Augustine Grass Weed & Feed (Sunniland) – 5000 sq ft | Weed control combined with feeding for moderate weed pressure | Easy-to-use granular weed-and-feed formulation |
| LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam | Professional-grade control in larger St. Augustine areas | Slow-release feeding with weed control for extended effect |
Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz
Best for: Homeowners with St. Augustine or centipede lawns dealing with broadleaf weeds. This quart-size bottle treats about 3,720 sq ft, making it suitable for medium to larger yards or for spot treatments in problem areas.
Why selected: Atrazine-based formulas are traditional choices for warm-season grasses, providing broadleaf weed control that is labeled for St. Augustine varieties. It’s straightforward to apply and offers a cost-effective option per coverage area.
Limitation: Atrazine products can be less effective on certain stubborn weeds and may require follow-up treatments for complete season-long control. Avoid use on sensitive ornamentals and follow label directions for safe application on St. Augustine turf.
Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon
Best for: Larger lawns with ongoing broadleaf weed challenges and needs for crabgrass suppression. The gallon size provides extended coverage for substantial St. Augustine areas.
Why selected: This product expands on the Atrazine approach with broadleaf weed-killing capability and additional suppression of crabgrass, helpful when weed variety is high.
Limitation: As with other Atrazine-based formulas, ensure proper timing and application to minimize impact on non-target plants and to respect seasonal guidelines for warm-season grasses.
PBI-Gordon Aethon Herbicide SL, 1 Quart
Best for: Warm-season grasses such as Floratam, Bermuda, and Zoysia, with a focus on tough weeds, including sedges and broadleaf weeds. Suitable for lawns needing stronger, long-lasting control.
Why selected: Aethon uses Vexis Technology to target weed root structures, slowing regrowth and reducing underground weed seeds and tubers. This is a solid choice when you want durable suppression beyond the surface weeds.
Limitation: Data emphasizes long-term performance; treat according to label timing and follow-up may be necessary for certain annual weed cycles.
Sunniland St.Augustine Weed & Feed Lawn Fertilizer
Best for: Home lawns seeking an all-in-one option that feeds while managing common broadleaf weeds in St. Augustine turf. Suitable for moderate weed pressure where fertilization is also a priority.
Why selected: Weed-and-feed products provide both nutrition and weed control in one step, which can simplify lawn care for busy homeowners. This option is compatible with standard St. Augustine grass varieties.
Limitation: Granular formulations may require precise timing and even distribution to ensure uniform weed control and nutrient delivery across the lawn.
LESCO 50 lb. St. Augustine Grass Weed and Feed with Penoxsulam
Best for: Larger St. Augustine lawns that benefit from professional-grade weed control with extended feeding. Penoxsulam targets a spectrum of weeds while providing slow-release nutrition.
Why selected: This product blends weed control with long-lasting fertilizer, designed for extended lawn health and weed suppression over weeks. It’s geared toward larger or high-traffic areas where durability matters.
Limitation: It’s a heavier product intended for bigger applications. Ensure proper spreading equipment and follow label timing to avoid over-application or uneven coverage.
Buying Guide: Key Considerations When Choosing a St. Augustine Herbicide
- Weed type and density: Identify whether broadleaf weeds, crabgrass, sedges, or multiple weed types dominate your lawn. Choose a product aligned to target weeds present.
- Turf compatibility: Confirm the product label lists St. Augustine varieties you have (including Floratam or other common variants). Some formulas are optimized for specific varieties.
- Spray vs. granules: Liquid concentrates may offer precise control; granules combine fertilization with weed suppression but require even distribution.
- Coverage area: Compare coverage per bottle or bag to estimate how many applications you need for your lawn size. Larger yards may benefit from gallon or 50 lb options.
- Seasonality and timing: Warm-season grasses have specific application windows. Plan applications when weeds are most susceptible and avoid stress periods for the turf.
- Environmental and safety considerations: Follow label directions for watering, irrigation restrictions, and safety precautions to protect non-target plants and wildlife.
- Follow-up needs: Some products require multiple treatments or combination with fertilizer programs for optimal results.
FAQ: Quick Answers For Buyers
- What is the best herbicide for St. Augustine grass overall? The choice depends on weeds present; Atrazine-based products work well for broadleaf weeds, while Aethon and Penoxsulam-based formulas address tougher weed problems and provide longer residual control.
- Can I use weed-and-feed products on St. Augustine lawns? Yes, but ensure the product is labeled for St. Augustine grass and apply according to the feeding and weed-control directions to avoid over-fertilization or chemical stress.
- Should I treat for crabgrass separately? Some products offer crabgrass suppression; if crabgrass is a major issue, choose a formulation that explicitly lists crabgrass control or plan a follow-up treatment as seasons progress.
- Is a gallon-size herbicide better than a quart for my yard? For larger lawns, a gallon or bulk option can reduce refills and lower per-square-foot cost. For small to medium yards, a quart may be sufficient.
- Are there any safety precautions for St. Augustine lawns? Always follow the label for application rates, timing, irrigation restrictions, and compatibility with other lawn care products to protect the turf and surrounding plants.
- Can these products harm St. Augustine varieties like Floratam? Most products label compatibility with Floratam and other common St. Augustine cultivars; verify the label for your specific variety before use.