Kill Monkey Grass Permanently (Step-by-Step)

To remove monkey grass for good, first confirm it is liriope, then remove every crown and as many underground rhizomes as possible, or use a herbicide labeled for the plant and site. Check for new shoots after two to four weeks and through the growing season. No single treatment guarantees permanent control.

Monkey grass can look like a simple border plant until you try to clear it. The leaves come away easily, but the crowns and underground stems can remain in the soil and send up new growth. I focus on removing those growing points, protecting nearby plants, and returning to check the area rather than treating one pass as the finish.

Identify Monkey Grass and Prepare the Site Safely

Liriope, often called monkey grass, grows in clumps or spreading patches from crowns and underground rhizomes. Mondo grass, or Ophiopogon, is also called monkey grass, so check the plant before choosing a control method. Correct identification helps you plan removal and avoid damaging plants you want to keep.

Liriope has narrow, grass-like leaves and may produce small flowers followed by dark berries. Depending on the type, it grows in clumps or spreads by short underground stems called rhizomes. A crown is the dense base where leaves and roots meet. A piece of crown or rhizome left in the soil may regrow.

Mondo grass can look similar, but it is a different plant. If you are unsure, compare the leaves, growth habit, flowers, and berries with a trusted local plant guide or ask a county extension office or nursery. Do not assume every plant sold under the common name “monkey grass” responds the same way.

Before digging or spraying:

• Mark nearby ornamentals, turf, and trees that must be protected.
• Locate irrigation lines and check for buried utilities before excavation.
• Decide how you will contain and dispose of the removed plants.
• If considering herbicide, read the full product label. Confirm it permits use on liriope and at your specific site.
• Check the label’s personal protective equipment (PPE), weather, rain-free interval, and re-entry directions.

Glyphosate is a nonselective systemic herbicide: it can move through a treated plant, but it can also injure any green tissue it contacts. Do not spray on a windy day or where drift or runoff could reach plants you want to keep. Keep people and pets out for the label’s stated re-entry period.

Remove Crowns and Rhizomes or Apply a Labeled Treatment

Hand digging suits small, accessible patches where you can reach the roots and sort through the soil. A labeled herbicide may be an option for larger patches or hard-to-dig areas, but only if the label allows that use. Choose one method based on the site, then plan to inspect for regrowth.

Step 1: Dig out a small patch

If the soil is dry and hard, lightly water the area first so it is easier to work. Do not soak it enough to make the ground muddy. Loosen soil around each clump with a hand fork or spade, then lift out the crown and attached roots.

Work outward from the edge of the patch. Pick through the loosened soil and remove visible rhizome pieces; avoid chopping or rototilling the patch, which can leave fragments behind or spread them through the bed. If a large root mass breaks apart, check the hole and sift the excavated soil before replacing it.

Put the removed plant material in a bag or other suitable container. Follow local rules for disposal. Do not add herbicide-treated material to compost unless the product label permits it.

Step 2: Treat a larger or difficult patch, if the label allows

For a patch that is too large or difficult to dig, read the product label and verify that it permits use on liriope at that location. Apply only by the labeled method and rate. There is no universal safe or effective concentration for every product and site, so do not substitute advice from a different product label.

Treat healthy, actively growing foliage under the label’s approved conditions. Follow all stated limits for wind, temperature, rain, PPE, and re-entry. Shield nearby plants and direct the treatment only onto the target foliage. Even a small amount of glyphosate on a desirable plant’s leaves or other green tissue can cause injury.

Key step: Choose a method you can carry out carefully and revisit. A fast first pass is not useful if it leaves viable roots or harms plants around the patch.

Field scenarios: match the method to the patch

These are practical site examples, not documented case studies. They show how the same removal plan changes with patch size and nearby plants.

• A few clumps in a mixed border: I would start with hand digging. It gives direct control near valued plants, though it takes time to remove the roots and inspect the soil.
• A dense strip with open space around it: Compare the time needed to dig the entire strip with a product label that permits treatment there. If treating, shield the edges and avoid drift.
• A patch tangled through groundcover: Work in small sections so you can identify what belongs and what must go. Digging may preserve nearby plants, but take care not to scatter rhizome pieces.

Inspect for Regrowth and Correct Control Failures

Follow-up is part of removal, not an optional extra. New shoots may come from crown or rhizome pieces missed during digging, or from plants that survived treatment. Inspect the cleared area about two to four weeks later, then continue checking through the growing season.

Mark the patch or take a photo after the first removal or treatment. This gives you a clear reference for the next inspection. Look for new leaves within the former planting area and around its edges, where rhizomes may have extended.

If you find isolated shoots, dig them out with the attached crown and roots when practical. Avoid mowing or chopping them into fragments. If you used herbicide, repeat treatment only when the label permits it and only under the stated conditions. Do not increase the rate or mix products to try to speed up control.

If there is no visible change after treatment, review what you did before applying more:

• Was the plant actively growing?
• Did the label permit the product and method for that site?
• Did rain occur within the label’s rain-free interval?
• Could spray have missed leaves or reached only part of the patch?
• Were weather or temperature limits exceeded?

A missed application window or incomplete coverage may explain poor results, but do not assume the cause. Follow the label and, if needed, ask the product maker or a local extension office for help. Continue checking throughout the season, and inspect again during the next growing season. Persistent shoots mean the patch still needs attention.

Restore the Bed and Monitor Through the Next Growing Season

Once the area is clear, restore it in a way that makes new shoots easy to spot. Follow any product label directions on when you may replant or cover a treated area. Keep monitoring through the next growing season, since a clean-looking bed does not prove every underground piece is gone.

After hand digging, refill low spots with suitable soil and avoid moving contaminated soil to another part of the yard. If you treated the foliage, wait as long as the label requires before planting or disturbing the area. Then replant or mulch as appropriate for the bed.

Keep the cleared area visible enough to inspect. A thick layer of mulch can hide emerging shoots, so check beneath it as you monitor. Remove new growth promptly, including its crown where you can reach it. If you are restoring a bed with other plants, choose plants suited to its light and soil conditions; healthy cover can make routine checks easier, but it does not replace them.

In site work, I treat the next growing season as a useful test of whether follow-up is working. New shoots do not mean the whole job failed; they show where a viable piece remains. Remove or treat that growth using the same careful method, then keep records of when and where it appears.

Frequently Asked Questions

These short answers cover common decisions after you find a monkey-grass patch. The key points are to identify the plant, follow the product label if using herbicide, and check for regrowth more than once.

Can monkey grass be removed permanently?
It can be controlled, but no single removal or treatment guarantees permanent control. Remove crowns and rhizomes, then monitor and remove any new shoots.

How long does it take to kill liriope?
There is no fixed timeline. Check about two to four weeks after the first treatment or removal, then continue inspections through the growing season and the next growing season.

Will digging kill monkey grass?
Digging can remove a small patch if you lift the crowns and as many rhizomes as possible. Pieces left in the soil may regrow, so inspect the excavated soil.

Does glyphosate kill monkey grass?
Glyphosate may control liriope when a specific product label permits use on that plant and site. It is nonselective and can injure desirable plants it contacts.

Can I spray glyphosate near flowers or trees?
Use it only as the label allows, and prevent contact with green tissue you want to keep. Shield nearby plants, avoid wind, and do not let spray drift or run off.

Should I rototill a monkey-grass patch?
No. Rototilling or chopping can leave or spread rhizome fragments, making follow-up harder. Dig carefully or use a labeled treatment where permitted.

What should I do with removed or treated plants?
Bag and dispose of them according to local rules. Do not compost herbicide-treated material unless the product label says it is permitted.

When can I replant after herbicide treatment?
Follow the product label’s planting and site directions. Labels differ, so do not rely on a general waiting period.

Why is monkey grass growing back after I dug it up?
A crown or rhizome piece may have remained, or growth may have come from just outside the area you cleared. Dig out isolated shoots and check the patch edges.

Is monkey grass the same as mondo grass?
No. Both may be called monkey grass, but liriope and mondo grass are different plants. Identify which one you have before choosing a control method.

(This article was written by one of our staff writers, Victor Dempsey. Visit our Meet the Team page.)