How to Kill Broadleaf Signalgrass in Zoysiagrass Without Hurting Your Lawn
Direct Agronomic Answer
To selectively kill Broadleaf Signalgrass in Zoysiagrass without damaging your turf, apply Drive XLR8 (Quinclorac 18.92%), Acclaim Extra (Fenoxaprop-p-ethyl 6.59%) when air temperatures are between 60°F and 85°F.
For Bermudagrass and Zoysia, Tribute Total or Celsius WG suppresses seedling infestations.
1. Labeled Safe Herbicides That Kill Broadleaf Signalgrass in Zoysiagrass
| Recommended Product | Active Ingredient & Group | Application Temp (°F) | Surfactant & Mixing Protocol | Where to Buy |
|---|---|---|---|---|
| Drive XLR8 EPA Reg. 7969-272 |
Quinclorac 18.92% Group 4 (Synthetic Auxin / Quinoline Carboxylic Acid) |
60°F – 85°F Rainfast: 1h |
Requires Methylated Seed Oil (MSO) surfactant at 1.5 tbsp (0.75 fl oz) per gallon of water for effective cuticle penetration on multi-tiller crabgrass. | Check Price at DoMyOwn View on Amazon |
| Acclaim Extra EPA Reg. 432-950 |
Fenoxaprop-p-ethyl 6.59% Group 1 (ACCase Inhibitor) |
60°F – 85°F Rainfast: 1h |
Add Non-Ionic Surfactant (NIS) at 0.5 tsp per gallon only when targeting mature multi-tiller Goosegrass or Japanese Stiltgrass. Never tank-mix with 2,4-D (causes antagonism). | Check Price at DoMyOwn View on Amazon |
3. Optimal Seasonal Timing & Temperature Thresholds
Apply post-emergent sprays in early summer when plants have 2 to 4 leaves.
Apply pre-emergent Prodiamine in spring before soil reaches 65°F.
4. Diagnostic Checklist: Confirm It Is Broadleaf Signalgrass Before Spraying
- Short, wide, lance-shaped leaves with crinkled or wavy margins on one edge
- Creeping decumbent stems rooting at lower nodes forming dense mats
- Seedhead branches positioned like railroad signal flags at right angles
Not 100% sure? Use our AI Photo Weed Scanner or review the full Broadleaf Signalgrass Botanical Profile.