Finding an effective weed killer for St. Augustine grass can be challenging, especially when you want to protect the turf while targeting common weeds. The following selections are tailored for St. Augustine and Centipede lawns, offering selective control with ingredients like atrazine and other formulations. Below is a concise overview to help guide a purchase decision, followed by in-depth product sections and a practicalBuying Guide to consider soil type, climate, and lawn maintenance routines.
| Product | Active Focus | Coverage | Best For |
|---|---|---|---|
| Southern Ag Atrazine St. Augustine Weed Killer (1 Gal) | Atrazine– broadleaf weed suppression | Large gallon size for extended use | St. Augustine & Centipede lawns |
| Southern Ag 006130 Atrazine St. Augustine Weed Killer (32 oz) | Atrazine– weed control | Treats thousands of sq ft per quart | St. Augustine & Centipede grasses |
| Hi-Yield (33431) Atrazine Weed Killer RTS (32 oz) | Atrazine– selective weed control | Up to ~3,720 sq ft per bottle | St. Augustine & Centipedegrass |
| Spectracide Weed Stop For Lawns (32 oz, 6-pack) | Atrazine– lawn-wide control | Ready-to-spray concentrate | St. Augustine & Centipede lawns |
| BioAdvanced Season Long Lawn Weed Killer + Preventer (10 lb) | Broadleaf & crabgrass prevention | 4,000 sq ft coverage | Southern lawns incl. St. Augustine |
Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon
Key features: Kills many broadleaf weeds; also used in centipede grass; provides suppression of crabgrass. This product is designed for St. Augustine lawns and offers a convenient, large-volume option for homeowners with bigger yards. Consider compatibility with your turf type and follow label directions for safe application.
Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz
Key features: One quart treats 3,720 sq ft; controls weeds in St. Augustine and Centipede grasses; packaged for easy handling. Useful for targeted seasonal weed suppression, especially in warm-season lawns where rapid growth of broadleaf weeds can occur.
Hi-Yield (33431) Atrazine Weed Killer RTS (32 oz)
Key features: Selective weed killer targeting henbit, clover, chickweed and more; intended for use on St. Augustine and Centipedegrass; 32 oz bottle treats up to 3,720 sq ft. Label details guide proper application to avoid turf injury and ensure effective weed control.
Hi-Yield Atrazine Weed Killer
Key features: Atrazine at 4.00% concentration; targets annual bluegrass, chickweed; designed for St. Augustine and Centipede grasses. Provides targeted weed suppression while aiming to preserve lawn health when used as directed.
Fertilome St. Augustine Weed & Feed 15-0-4
Key features: Pre-emergent and post-emergent weed control with 15-0-4 fertilizer; designed for Centipede, Zoysia, and St. Augustine lawns; not for Bermuda or other Northern grasses. Useful for seasons requiring both weed suppression and immediate fertilization to support lawn recovery.
Spectracide Weed Stop For Lawns (St. Augustine & Centipede)
Key features: Kills weeds, not the lawn; includes atrazine for broad-spectrum control; suitable for all St. Augustinegrass varieties and centipedegrass when used as directed. The Ready-to-Spray format simplifies application for busy homeowners.
BioAdvanced Season Long Lawn Weed Killer + Preventer (10 lb)
Key features: Kills and prevents weeds for up to 6 months; covers 4,000 sq ft; suitable for all southern lawns including St. Augustine; provides a residual effect to deter weed regrowth after initial treatment. Label directions help ensure proper timing and safety for desirable grasses.
BioAdvanced 3-in-1 Weed and Feed for Southern Lawns
Key features: Specially formulated for Southern lawns; provides up to 6 months of weed prevention; kills listed weeds like dandelion, dollarweed, and clover; acts as a lawn fertilizer alongside weed control to maintain lawn health and appearance.
Buying Guide
Weed type and target: Identify whether your primary concern is broadleaf weeds (dandelion, clover) or grassy weeds (crabgrass). Many products use atrazine as a broad-spectrum option for St. Augustine lawns, but check the label for the specific weeds listed and any restrictions for Centipede grass as well.
Turf compatibility: Confirm that the product explicitly lists St. Augustine or Floratam varieties on the label. Some formulations are also labeled for Centipede grass, which helps ensure safe use across mixed lawns. Avoid applying products labeled only for other grass types on St. Augustine.
Active ingredient and concentration: Atrazine-based products are common for warm-season lawns; however, non-atrazine options may be safer for some landscapes. Review concentration and application rates to balance effectiveness with turf safety.
Delivery form and coverage: Choose based on yard size and preferred application method. Ready-to-Spray products save time, while concentrates may reduce waste for large areas. Calculate square footage to match bottle coverage and avoid over- or under-application.
Seasonality and preventers: Some products offer preventive action lasting several months, reducing weed emergence in subsequent seasons. Consider a program that combines weed control with fertilization for overall lawn health, but follow label guidance regarding timing and compatibility with your turf.
Lawn safety and restrictions: Always read the label for safety instructions, water-use guidelines, and restrictions on nearby desirable plants, ponds, or pets. Certain herbicides are not suitable for Bermuda or cool-season grasses and may harm non-target plants if misapplied.
Environmental considerations: Use the minimum effective rate, avoid runoff into storm drains, and consider weather conditions. Applying when rain is forecast soon after treatment can reduce efficacy and increase environmental impact.
Maintenance integration: For ongoing lawn health, pair weed control with proper mowing height, irrigation, and fertilization. A healthy, well-maintained St. Augustine lawn is naturally more resistant to weed establishment.