How To Kill Monkey Grass: Permanent Eradication Methods For Liriope And Mondo Grass

Effectively eliminating persistent monkey grass (Liriope muscari, Liriope spicata, or Ophiopogon japonicus) requires a systematic combination of systemic herbicide application, aggressive mechanical removal, or exhaustive solarization to destroy its dense, tuberous root systems. Because these perennial monocots store massive energy reserves in their thick rhizomes and tubers, surface-level pulling or single herbicide sprays routinely fail, necessitating a multi-step eradication strategy tailored to the scale of infestation.

Pre-Operation & Planning for Total Eradication

Successfully eradicating monkey grass demands careful preparation to prevent accidental damage to desirable turfgrass or ornamental plants while ensuring the chosen treatment reaches deep into the subterranean root network. Monkey grass spreads aggressively via underground stolons and forms tightly knit clumps that easily regenerate from any surviving root fragments left behind in the soil matrix.

• Essential Gear, Tools, and Materials: Pump sprayer or backpack sprayer, glyphosate-based non-selective systemic herbicide (minimum 41% active ingredient), heavy-duty garden spade, pitchfork, landscape fabric or clear 6-mil polyethylene plastic, heavy-duty work gloves, and protective eyewear.
• Mandatory Prerequisite Knowledge and Standards: Identify whether your infestation is clump-forming (Liriope muscari) or running/creeping (Liriope spicata); running varieties require a wider perimeter barrier during mechanical removal. Never apply non-selective herbicides on windy days to prevent drift damage to nearby desirable vegetation.
• Estimated Budget and Duration Benchmarks: Material costs range from twenty to sixty dollars depending on herbicide selection and tarp coverage. The operational timeline spans from two weeks for chemical kill-off to eight weeks if utilizing solarization.

Step-by-Step Eradication Workflow

Step 1: Foliar Preparation and Mowing

Before applying any systemic control method, lower the resistance of the thick waxy leaves by mowing or weed-whacking the monkey grass down to approximately two inches above the soil line. Removing the upper canopy forces the plant to redirect its energy reserves upward while allowing herbicides or solarization materials to make closer contact with the crown and new shoots.

Pro-Tip: Rake away all clippings and debris immediately after cutting to expose the central crowns of the monkey grass clumps to subsequent treatments.

Step 2: Systemic Herbicide Application

Mix a high-potency, non-selective systemic herbicide containing glyphosate at a rate of 2.5 to 3 ounces per gallon of water, adding a non-ionic surfactant to help the solution adhere to the remaining waxy foliage. Spray the actively growing monkey grass foliage thoroughly on a calm, sunny day when temperatures are consistently above 60 degrees Fahrenheit.

Warning: Glyphosate is completely non-selective and will kill any green plant tissue it touches, so use a physical cardboard shield or precision spray nozzle to protect nearby turf and ornamentals.

Step 3: Mechanical Excavation of Dead or Stressed Tissue

Allow seven to fourteen days for the systemic herbicide to translocate down to the deepest tubers and kill the root network, indicated by complete browning and desiccation of the plant. Insert a sharp garden spade or pitchfork at a 45-degree angle approximately six inches outside the perimeter of the monkey grass clump to pry up the entire root ball.

Pro-Tip: Sift through the excavated soil with a cultivator to extract every piece of fleshy, tuberous rhizome, as even small left-behind segments will sprout new growth.

Step 4: Soil Solarization for Large Infestations

For vast beds heavily infested with running monkey grass where digging is impractical, cover the entire treated area with heavy-duty 6-mil clear polyethylene plastic sheeting. Anchor the edges securely with soil, stones, or landscape staples, and leave the plastic in place for six to eight weeks during the peak heat of summer to bake the soil and destroy remaining underground tubers.

Comparative Analysis of Monkey Grass Eradication Methods

Common Site Failures and Field Fixes

• Root Regeneration from Residual Tubers:
  
  
  • Root Cause: Small, segmented rhizomes or tubers were left buried in the soil during manual excavation, allowing the plant to rapidly clone itself.
  • Actionable Fix: Monitor the area weekly for emerging shoots, spot-treat new growth immediately with a targeted systemic herbicide, or re-excavate the specific pocket using a soil knife.
• Incomplete Herbicide Translocation:
  
  
  • Root Cause: Applying herbicide during drought-stressed conditions causes the plant to shut down its vascular system, preventing the chemical from reaching the roots.
  • Actionable Fix: Water the monkey grass thoroughly for three days prior to herbicide application to ensure active translocation, and re-apply only when new green growth emerges.
• Chemical Drift Damage to Turfgrass:
  
  
  • Root Cause: Spraying on a windy day or failing to use a physical barrier around desirable lawns and flower beds.
  • Actionable Fix: Immediately flush affected desirable turf with copious amounts of water if caught early, or prune back severely damaged perennial ornamentals and apply a balanced fertilizer to encourage recovery.

Frequently Asked Questions

Will pulling monkey grass out by hand kill it permanently?

Manual pulling rarely achieves permanent eradication unless every single subterranean tuber and rhizome is completely removed from the soil. Because monkey grass possesses thick, fleshy storage roots that snap off easily and regenerate, pulling often stimulates dense new growth from the leftover underground fragments.

How long does glyphosate take to kill monkey grass?

Glyphosate typically requires between 10 to 21 days to fully translocate through the vascular system of monkey grass and kill the root structure. Complete browning of the foliage signals that the chemical has worked, but a second application is frequently required for dense, established stands.

Can I smother monkey grass with cardboard and mulch instead of digging?

Sheet mulching is effective for smothering monkey grass, but it requires a thick layer of overlapping corrugated cardboard covered by at least four inches of organic mulch. This method can take up to six months to completely exhaust the energy reserves in the underground tubers.

What is the absolute fastest way to get rid of monkey grass?

The fastest eradication method combines cutting the foliage to the ground, applying a high-concentration systemic glyphosate herbicide, and mechanically excavating the dead root balls one week later. This dual-action approach destroys both the top growth and the stubborn underground tubers simultaneously.

Start your landscape transformation today by implementing these proven eradication techniques to permanently reclaim your garden beds from invasive monkey grass.