Broadleaf Signalgrass (Urochloa platyphylla): Identification & Selective Herbicide Matrix
Quick Agronomic Summary
Quinclorac (Drive XLR8) applied with MSO surfactant provides excellent control in tolerant turf types.
- Diagnostic Marker 1: Short, wide, lance-shaped leaves with crinkled or wavy margins on one edge
- Diagnostic Marker 2: Creeping decumbent stems rooting at lower nodes forming dense mats
- Diagnostic Marker 3: Seedhead branches positioned like railroad signal flags at right angles
What kills Broadleaf Signalgrass in lawns?
Quinclorac (Drive XLR8) applied with MSO surfactant provides excellent control in tolerant turf types.
For Bermudagrass and Zoysia, Tribute Total or Celsius WG suppresses seedling infestations.
When to treat Broadleaf Signalgrass?
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.
EPA-Registered Herbicides Labeled for Broadleaf Signalgrass
The table below compares all selective herbicides in our database that control Broadleaf Signalgrass, including active ingredient groups, application temperature limits (°F), and surfactant requirements.
| Brand Name & EPA Reg. | Active Ingredient & WSSA Group | Temp Window (°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 |
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Turfgrass Compatibility Matrix for Broadleaf Signalgrass Herbicides
Always verify that your chosen herbicide is safe for your specific lawn grass before broadcast spraying:
How to Distinguish Broadleaf Signalgrass from Lookalike Weeds
| Lookalike Species | Key Botanical & Diagnostic Difference |
|---|---|
| Crabgrass | Signalgrass has much broader blades with wavy edges and signal-flag-like seed branches, unlike the finger-like spikes of Crabgrass. |