Green Foxtail
Setaria viridis
Green Foxtail (Setaria viridis) is a summer annual grassy weed characterized by similar to yellow foxtail but with soft green to purple bristled seed heads; smooth leaf sheaths lacking long hairs at base.. It anchors via a fibrous roots root system and is selectively controlled using Pendimethalin or Prodiamine (Pre-emergent) applied during early spring pre-emergent timing alongside crabgrass..
Pendimethalin or Prodiamine (Pre-emergent)
Similar to yellow foxtail but with soft green to purple bristled seed heads; smooth leaf sheaths lacking long hairs at base.
Always read and follow the manufacturer's EPA-approved pesticide product label. The label is the law under federal FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act) regulations. Application rates, personal protective equipment (PPE), target weed maturity stages, temperature restrictions, and grazing or re-entry intervals specified on the EPA container label supersede all online recommendations. Local state regulations may restrict certain active ingredients.
University-Verified Herbicide Formulations
Professional active formulations cross-referenced against university weed science trials.
Tenacity Herbicide (Mesotrione 8 oz)
Active: 40% Mesotrione Selective Systemic
Gold standard selective pre- and post-emergent targeting crabgrass, ground ivy, yellow nutsedge, and clover during overseeding.
SedgeHammer+ Turf Herbicide (Halosulfuron 0.5 oz)
Active: 5% Halosulfuron-methyl with Surfactant
Pre-mixed with surfactant for 1-gallon sprayers. Translocates into underground nutlets without injuring cool or warm season lawns.
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Botanical Identification Key for Green Foxtail
Accurately identifying Setaria viridis is essential because spraying non-selective chemicals like glyphosate risks killing desirable lawn grass. Look for these botanical hallmarks:
- Foliar Morphology: Similar to yellow foxtail but with soft green to purple bristled seed heads; smooth leaf sheaths lacking long hairs at base..
- Root Architecture: Anchored by a fibrous roots, making manual pulling ineffective unless the entire root crown is extracted.
- Growth Period: Active during summer annual cycles, flourishing when lawn turf is stressed or cut too short.
Eradication Protocol & Selective Herbicide Selection
To eradicate Green Foxtail while preserving your lawn turfgrass, apply Pendimethalin or Prodiamine (Pre-emergent) during Early spring pre-emergent timing alongside crabgrass.. Ensure that the active ingredients match your host turfgrass tolerances:
- Temperature Safety Band: Apply when ambient air temperatures range between 65°F and 85°F. Never apply volatile ester herbicides in temperatures exceeding 85°F to prevent herbicide vapor drift and leaf burn.
- Adjuvant / Surfactant: For waxy or hairy weed foliage, mix with a methylated seed oil (MSO) or non-ionic surfactant according to EPA label instructions to enhance chemical cuticle penetration.
- Mowing Holdback: Do not mow the lawn 2 days prior to spraying or 2 days after application to maximize foliar surface area for chemical absorption.
Frequently Asked Questions About Green Foxtail
01 How do I kill Green Foxtail without harming my lawn?
Use a selective herbicide labeled for your specific turfgrass species containing Pendimethalin or Prodiamine (Pre-emergent). Spray when Green Foxtail is actively growing during early spring pre-emergent timing alongside crabgrass.. Always check your host grass in our weed triage tool before application.
02 Why does pulling Green Foxtail by hand often fail?
Green Foxtail anchors via a fibrous roots. Hand-pulling often breaks the crown or leaves underground root fragments, rhizomes, or nutlets behind, which triggers rapid regrowth. Systemic selective herbicides translocate down through the vascular tissue to destroy the entire root structure.
03 What class of weed is Green Foxtail?
Green Foxtail is classified botanically as a Grassy weed with a Summer Annual life cycle.
04 When is the best time of year to treat Green Foxtail?
The optimal eradication window is Early spring pre-emergent timing alongside crabgrass.. Applying when temperatures are between 60°F and 85°F ensures maximum chemical absorption and prevents foliar heat stress to your desirable lawn.