How to Kill Torpedograss in St. Augustinegrass Without Hurting Your Lawn
Direct Agronomic Answer
Selective control of Torpedograss in St. Augustinegrass requires extreme caution; avoid broadcast spraying non-compatible herbicides and use targeted spot applications.
Torpedograss is nearly impossible to remove selectively from St. Augustine or Centipede without killing the turf. Multiple Quinclorac applications with MSO suppress rhizomes in Bermuda.
1. Labeled Safe Herbicides That Kill Torpedograss in St. Augustinegrass
No broadcast selective herbicide is rated unconditionally safe for this combination. Check the conditional options below or spot-treat individual weed crowns with a foam brush.
2. What NOT to Spray on St. Augustinegrass When Treating Torpedograss
Warning: Common Torpedograss Killers That Damage St. Augustinegrass
Many retail herbicides advertised for Torpedograss are formulated for different turf zones and will severely injure St. Augustinegrass:
- AVOID Drive XLR8 (Quinclorac 18.92%): Rated 'avoid' on St. Augustinegrass — high risk of turf phytotoxicity or stunting.
3. Optimal Seasonal Timing & Temperature Thresholds
Apply in late spring and summer during vigorous active growth, repeating after 21 days.
Never cultivate or till soil infested with Torpedograss as chopped rhizome fragments spread the infestation.
4. Diagnostic Checklist: Confirm It Is Torpedograss Before Spraying
- Stiff, hard, sharp, torpedo-like pointed rhizome tips that punch through sod and weed fabrics
- Linear, flat or folded pale blue-green blades with fine hairs on upper surface
- Open, loose, panicle-type seedhead with branches pointing upward
Not 100% sure? Use our AI Photo Weed Scanner or review the full Torpedograss Botanical Profile.