How to Kill Dallisgrass in Tall Fescue Without Hurting Your Lawn
Direct Agronomic Answer
To selectively kill Dallisgrass in Tall Fescue without damaging your turf, apply Pylex Herbicide (Topramezone 29.7%) when air temperatures are between 55°F and 85°F.
Dallisgrass is a deep-rooted perennial bunchgrass that resists most selective herbicides. Multiple post-emergent applications are necessary to starve the deep rhizome system.
1. Labeled Safe Herbicides That Kill Dallisgrass in Tall Fescue
| Recommended Product | Active Ingredient & Group | Application Temp (°F) | Surfactant & Mixing Protocol | Where to Buy |
|---|---|---|---|---|
| Pylex Herbicide EPA Reg. 7969-327 |
Topramezone 29.7% Group 27 (HPPD Inhibitor / Pyrazolone) |
55°F – 85°F Rainfast: 1h |
Must be applied with Methylated Seed Oil (MSO) at 1 to 1.5 tsp per gallon of water. Tank-mixing with Triclopyr Ester reduces white bleaching and speeds up Bermudagrass and Goosegrass mortality. | Check Price at DoMyOwn View on Amazon |
3. Optimal Seasonal Timing & Temperature Thresholds
Treat in late summer to early fall when plants are translocating carbohydrates to rhizomes.
A spot treatment in late spring followed by an autumn application yields the highest mortality.
4. Diagnostic Checklist: Confirm It Is Dallisgrass Before Spraying
- Large, coarse, circular bunches with a dead, hollowed-out center as clumps age
- Wide, coarse leaf blades with a prominent midrib and hair on lower leaf sheaths
- Seedhead consists of 3 to 5 alternating drooping branches with black, caterpillar-like hairs on seeds
Not 100% sure? Use our AI Photo Weed Scanner or review the full Dallisgrass Botanical Profile.