Choosing a weed killer that protects St. Augustine grass while effectively tackling common weeds is essential for a healthy lawn. The following selections are designed to target broadleaf and grassy weeds without harming St. Augustinegrass when used as directed. Below you will find concise product profiles, a quick comparison, and practical buying considerations to guide your purchase.
| Product | Active Focus | Typical Use | Notes |
|---|---|---|---|
| Southern Ag 006130 Atrazine St. Augustine Weed Killer | Atrazine | St. Augustine & Centipede | Treats up to 3,720 sq ft |
| Hi-Yield Atrazine Weed Killer | Atrazine | St. Augustine & Centipede | Treats up to 3,720 sq ft |
| Ortho WeedClear Weed Killer for Lawns Concentrate | Multiple listed weeds | St. Augustinegrass (not Floratam) and more | Concentrate, fast-acting |
| Ortho WeedClear Weed Killer for Lawns with Trigger Sprayer | Over 250 weeds | St. Augustinegrass (not Floratam) and more | Sprayer-ready |
| Liquid Harvest Mesotrione | Mesotrione | Broad lawn use including St. Augustine (sod) | Pre and post-emergent |
Table notes: Always read label directions for St. Augustinegrass compatibility, especially for Floratam varieties. Apply only as directed and consider your region’s climate and grass type to minimize risk to nearby ornamentals and wildlife.
Southern Ag 006130 Atrazine St. Augustine Weed Killer
Product details indicate this quart-sized formulation treats up to 3,720 square feet and targets common weeds in St. Augustine and centipede grasses. Atrazine-based products are selective herbicides designed to control broadleaf and some grassy weeds while preserving the turf when used properly. The package weight is listed at about 1.021 kilograms, providing a compact option for mid-season weed management.
Hi-Yield Atrazine Weed Killer
Hi-Yield Atrazine offers selective weed control aimed at St. Augustine and centipede grasses. The bottle is sized for treating roughly 3,720 square feet, making it a practical option for homeowners tackling a few weed patches. The label notes effectiveness against weeds such as Henbit, Clover, and Chickweed, among others, when applied as directed. Always verify local label compliance for your grass variety.
Ortho WeedClear Weed Killer for Lawns Concentrate
This concentrate is designed to kill more than 250 listed weeds, including dandelion and clover, down to the root while protecting your lawn when used as directed. It is suitable for St. Augustinegrass varieties (not Floratam) and other common turfgrasses, making it a versatile option for mixed-lawns. Its fast-acting formula aims to show results after a single application when used properly and sparingly on individual weeds.
Ortho WeedClear Weed Killer for Lawns with Trigger Sprayer
This spray-ready product targets more than 250 listed weeds and kills them down to the root. It is designed for St. Augustinegrass (not Floratam) and several other turfgrasses, making it a convenient option for homeowners who prefer a ready-to-use solution. The product is noted for being rainproof relatively quickly and offering effective one-application results when applied according to the label.
Liquid Harvest Mesotrione
Mesotrione-based products, including Liquid Harvest Mesotrione, offer a pre- and post-emergent approach suitable for a range of lawns, including St. Augustine grass (sod). Activation depends on adequate watering, and results may take 2–3 weeks to show full weed death. It targets broadleaf species and various grasses, providing flexibility for different lawn challenges while minimizing impact on the turf when used as directed.
Buying Guide: Key Purchase Considerations and Comparisons
When selecting a weed killer for St. Augustine lawns, consider the following:
- Grass compatibility: Some products specify “St. Augustinegrass (not Floratam)” or “St. Augustine & Centipede,” which helps ensure safety for your turf variety. Verify your grass type before purchase.
- Weed coverage: If your lawn has many weeds, choose products advertised as protecting against 250+ weeds. For targeted infestations, a more specific option may suffice.
- Form and application: Sprayer-ready formulas save preparation time, while concentrates require mixing. Ensure you have the proper equipment and follow label instructions closely.
- Pre- vs. post-emergent: Pre-emergent products prevent weed seeds from germinating, while post-emergent products kill existing weeds. Some products offer both modes, which can be advantageous for ongoing maintenance.
- Local regulations and Floratam caution: St. Augustine lawns in certain regions may be sensitive to specific herbicides. Always consult the product label and local extension service guidance for your area.
- Safety and environmental impact: Use protective gear as recommended, avoid runoff into nearby ornamentals or water sources, and observe any restricted-use warnings.
From the options above, the Southern Ag and Hi-Yield atrazine products provide a focused approach for St. Augustine and Centipede grasses, while Ortho WeedClear variants offer broad-spectrum, lawn-safe performance when used as directed. Liquid Harvest Mesotrione provides an alternative mechanism suitable for broad lawn applications with appropriate watering and crop-safety considerations. Compare labels, check compatibility with your specific St. Augustine variety, and choose the formulation that aligns best with your weed profile and maintenance routine.