Answering the question: which herbicides are safe and effective for St Augustine lawns? This guide highlights products designed to control common weeds in St Augustine grass without excessive risk to the turf. Ideal buyers include homeowners seeking selective weed control, turf managers maintaining warm-season lawns, and gardeners targeting broadleaf and grassy weeds in St Augustine, Centipede, or nearby Bermudagrass blends. The table below compares five top options to help you decide quickly.
| Product | Brand | Best For | Active Focus | Notes |
|---|---|---|---|---|
| Southern Ag 006130 Atrazine St. Augustine Weed Killer 32oz | Southern Ag | St Augustine and Centipede lawns needing broadleaf weed suppression | Atrazine-based weed control | Treats up to 3,720 sq ft |
| Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon | Southern Ag | St Augustine and centipede grass; broadleaf weed suppression | Broadleaf weed control and crabgrass suppression | Versatile gallon format |
| Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon & Surfactant (16oz) | Southern Ag | St Augustine and centipede; easier application with surfactant | Broadleaf weeds and crabgrass suppression | Combination package for improved coverage |
| Atticus Azion XP MSM Turf Herbicide (8-oz) | Atticus | Bermudagrass and St. Augustine turf weeds | Metsulfuron-methyl based selective postemergence control | Targets emerged weeds; avoid other turfgrass species per label |
| Image Herbicides Nutsedge Killer for Southern Lawns Concentrate 24 fl. oz. | Image Herbicides | Southern lawns with nutsedge, dandelions, and grasses | Postemergent, selective for southern turf | Contains targeted weed spectrum; follow label for turf compatibility |
NOTE: Always read and follow label directions to protect St Augustine lawns from potential injury. The selections below provide a mix of traditional atrazine-based products and newer selective herbicides designed to minimize turf stress when used correctly.
Southern Ag Atrazine St Augustine Weed Killer 32oz
Active ingredient is atrazine, designed to control broadleaf weeds in St Augustine and centipede grasses. Best for buyers who want a straightforward, pre-macronutrient weed killer with a wide coverage per quart (treats up to 3,720 sq ft). Caution: Atrazine can injure some turf varieties if misapplied or used on stressed turf. Selection is best for larger lawns with established St Augustine patches.
Southern Ag Atrazine St. Augustine Grass Weed Killer, 1 Gallon
This gallon-size option emphasizes broadleaf weed control and crabgrass suppression, with compatibility for St Augustine and centipede grasses. Best for homeowners seeking a flexible, large-volume treatment. Limitation: May require careful timing with crabgrass pressure and adequate irrigation to maximize effectiveness.
Southern Ag Atrazine St Augustine Grass Weed Killer, 1 Gallon & Surfactant
Includes Atrazine-based weed control plus a nonionic surfactant to improve leaf coverage. Best for buyers who want enhanced weed contact and coverage. Choose this if you suspect poor leaf wetting. Caution: Do not exceed labeled rates; misapplication can affect St Augustine blades or nearby ornamentals.
Atticus Azion XP MSM Turf Herbicide (8-oz)
Azion XP uses 60% metsulfuron-methyl for selective postemergence weed control in Bermudagrass and St Augustine grass. Best for actively growing, emerged weeds such as ryegrass or Virginia buttonweed. Not suitable for all turfgrass types—do not apply to non-target species. Choose this when targeting tough emerged weeds in St Augustine lawns and nearby Bermudagrass patches.
Image Herbicides Nutsedge Killer for Southern Lawns Concentrate 24 fl. oz.
Designed for southern lawns, including St Augustine, with nutsedge control and additional weed suppression such as dandelions and crabgrass. Best for buyers dealing with nutsedge-heavy patches. Limitation: Effectiveness depends on timing and callout of target weeds; verify compatibility with your exact grass variety before use.
Hi-Yield Grass Killer Postemergence (8 oz)
This product targets weed grasses post-emergence. Best for buyers who need quick suppression of unwanted grasses in mixed-tertilized lawns and around ornamentals. Caution: It can affect desirable grasses if misapplied or used in non-target areas; follow label directions carefully.
Buying Guide: Key Purchase Considerations
- Grass type compatibility: Ensure the product is labeled for St Augustine or Bermudagrass in your region. Some formulas are turf-specific and can injure non-target grasses if misapplied.
- Weed target: Identify dominant weeds (nutsedge, crabgrass, broadleaf weeds) to choose the most effective active ingredient (atrazine, metsulfuron-methyl, or broadleaf herbicides).
- Season and emergence: Postemergence applications work best on actively growing weeds; pre-emergence products prevent seedlings but may be less effective on established patches.
- Application method: Surfactants can improve coverage; follow label directions for mixing ratios and sprayer settings to avoid leaf burn.
- Turf health: Avoid applying during drought, heat waves, or when lawns are stressed to minimize injury risk.
- Safety and environment: Use protective gear as directed and keep away from water sources and ornamentals not listed on the label.
Frequently Asked Questions
- Which herbicide is best for St Augustine with heavy nutsedge?
– Nut sedge-focused products (such as Image Nutsedge Killer) can be effective when weeds are actively growing and label directions are followed. - Can I mix Atrazine with other lawn products?
– Only mix if the product label explicitly permits it; improper mixing can harm turf. - Is postemergence control sufficient for crabgrass in St Augustine lawns?
– Postemergence can reduce existing weeds, but crabgrass prevention may require pre-emergence strategies or timed applications. - How much product should I apply per 1,000 sq ft?
– Follow the label’s exact rate per square footage; over-application increases turf injury risk. - Are these products safe for nearby ornamentals?
– Some atrazine-based products can drift and affect ornamentals; always apply with proper containment and wind considerations. - What’s the best approach if I have a mixed lawn with St Augustine and centipede?
– Choose a product labeled for both St Augustine and centipede grasses to maximize weed control while minimizing turf injury.