Quinclorac (Drive XLR8 / Quintessential)

Overview

Quinclorac is the most effective post-emergent herbicide for killing emerged crabgrass at any growth stage. It is the community’s consensus recommendation whenever crabgrass breaks through pre-emergent protection or no pre-emergent was applied.

How It Works

Quinclorac is a synthetic auxin herbicide that disrupts growth regulation in crabgrass, causing uncontrolled growth that leads to plant death. It also controls some broadleaf weeds including clover.

Critical: Use MSO Surfactant

Quinclorac requires methylated seed oil (MSO) surfactant to work effectively. Do NOT skip the surfactant or substitute non-ionic surfactant — the product will underperform significantly. MSO helps the herbicide penetrate the waxy leaf surface of crabgrass.

Grass Safety

Safe on cool-season grasses and most warm-season grasses. NOT safe on St. Augustine or centipede — it will damage or kill these grasses. Safe to use on newly established grass after 3 mows.

Timing

Can be applied whenever crabgrass is actively growing (typically June through September). Effective at any growth stage, from seedlings to mature plants.