How To Kill Pampas Grass

If you’re wondering how to kill pampas grass, you’ve come to the right place. This ornamental grass can become a stubborn invasive problem, and effective removal requires a solid plan.

Its beautiful plumes hide a tough, deep root system. Left unchecked, it spreads fast and crowds out native plants. I’ll walk you through the best methods, from digging it out to using herbicides safely.

We’ll cover the tools you need and the timing that makes all the difference. Let’s get started on reclaiming your garden.

Successfully killing pampas grass means attacking the entire crown and root system. The plant stores energy in its base, so just cutting the tops won’t work.

You have a few main options. The best choice depends on the size of your clump, your budget, and whether you want to avoid chemicals.

Understanding Your Enemy: Pampas Grass Biology

Knowing how this grass grows helps you beat it. Pampas grass forms a massive, dense crown at ground level.

From this crown, it sends out roots deeply and widely. It also produces millions of seeds from those fluffy plumes.

Any removal plan must address three threats:

The mature crown and roots.
Seedlings sprouting from dropped seeds.
Potential regrowth from leftover root fragments.

Manual Digging: The Most Thorough Method

For smaller clumps or organic gardens, digging is the gold standard. It’s hard work but provides immediate, chemical-free results.

You’ll need the right tools to make it manageable. Don’t skimp here—good tools save your back.

Essential Tools for Digging

A sharp, pointed shovel with a strong handle.
A digging fork or pickaxe for breaking tough roots.
Heavy-duty loppers or a pruning saw.
Sturdy gloves and eye protection.
A tarp for collecting debris.

Step-by-Step Digging Process

Follow these steps carefully to ensure you get the whole plant.

Cut it Back: First, use loppers or a saw to cut the entire clump down to about 12 inches tall. This gives you access to the base. Tie the tops together with twine before cutting for easier handling.
Water the Soil: Water the ground around the clump thoroughly a day before digging. Moist soil is much easier to dig than hard, dry dirt.
Dig a Trench: Start digging a trench in a circle about 2 feet out from the center of the clump. Your goal is to isolate the root ball.
Undercut the Root Ball: Once you’ve dug deep enough (often 1-2 feet), start angling your shovel under the crown. Use the pickaxe to sever stubborn, deep roots.
Lift and Remove: Work the clump free and lift it onto the tarp. Check the hole for any remaining white root pieces and remove them all.
Dispose Properly: Do not compost the crown or plumes. Bag them and send to landfill, or burn if local regulations allow. This prevents any chance of spreading.

Using Herbicides: A Effective Chemical Approach

For large, established stands, a systemic herbicide is often the most practical solution. These chemicals are absorbed by the plant and translocated to the roots.

Glyphosate is a common choice, but you must use it correctly. Always read and follow the product label exactly.

Best Practices for Herbicide Use

Apply in late summer or early fall when the plant is actively moving nutrients to its roots.
Use a concentrated formula and mix according to label instructions.
Spray on a calm, dry day to prevent drift to desirable plants.
Wear protective clothing, gloves, and a mask.

Application Method: Cut-Stump Technique

This method maximizes herbicide effectiveness while minimizing the amount used.

Cut the pampas grass down close to the ground, as in the digging method.
Immediately paint or spray the freshly cut stump with herbicide. The fresh cut allows direct absorption into the vascular system.
Allow several weeks for the herbicide to work. You may see browning and die-back.
Re-treat any new green shoots that appear promptly.

Smothering: A Slow but Chemical-Free Option

Smothering, or solarization, works by depriving the plant of light. It’s less labor-intensive but takes much longer—often a full growing season.

This method is best for areas where you’re not in a hurry.

Cut the grass down as low as possible.
Cover the entire area with heavy, UV-stabilized black plastic or a thick layer of cardboard.
Overlap edges by at least a foot and secure them with rocks or soil.
Leave the cover in place for 6-12 months to ensure the roots and crown are completely dead.

Preventing Regrowth and Seed Spread

Your job isn’t done once the main clump is gone. Vigilance is key for the next year or two.

Monitor the area monthly for seedlings or root sprouts. Pull or spot-treat them immediately while they’re small.
Consider planting desirable, competitive plants in the area to crowd out any pampas grass attempts.
If you have neighboring pampas grass, talk to your neighbor about removal or ensure you cut plumes before they seed.

Timing is Everything: When to Attack Pampas Grass

The season you choose for removal greatly impacts your success. Late summer to early fall is generally the best window.

At this time, the plant is sending energy down to its roots for winter storage. Herbicides applied then are more effectively drawn down into the root system.

Spring removal is possible, but the plant is focused on top growth. You may see more vigorous regrowth that needs follow-up.

What Not to Do: Common Mistakes

Avoid these errors that can make your problem worse.

Just Burning or Mowing: This only removes the top growth and stimulates the crown to regrow even thicker.
Improper Disposal: Tossing clumps or plumes in the woods or compost creates new infestations. The seeds remain viable for years.
Giving Up Too Soon: Pampas grass is persistent. Expect to manage a few sprouts over the next season—this is normal, not failure.
Using the Wrong Herbicide: Some herbicides only kill leaves (contact herbicides). You need a systemic type like glyphosate.

FAQs About Removing Pampas Grass

Will vinegar kill pampas grass?

Household vinegar is not a reliable solution. It may burn the leaves, but it won’t kill the deep root system. The plant will almost always regrow.

How deep are pampas grass roots?

They can be surprisingly deep, often reaching 1 to 2 feet down and spreading just as wide. That’s why surface-level attacks fail.

Can I hire someone to remove it?

Yes, landscaping or tree service companies often handle large pampas grass removal. Get a quote that guarantees removal of the crown and roots.

How long does it take to kill it with herbicide?

You’ll see leaf browning in 1-2 weeks, but complete root death takes longer. Wait 4-6 weeks before assessing if a second application is needed.

Is pampas grass illegal to grow?

In some areas, yes. It’s considered a noxious weed in places like California, Hawaii, and parts of Australia. Check your local regulations.

What should I plant after removal?

Choose native grasses or shrubs that fit your climate. They’ll be easier to manage and support local wildlife, unlike the invasive pampas.

Removing pampas grass is a significant garden project, but it’s absolutely achievable with patience and the right approach. Start by choosing the method that fits your situation—whether it’s the physical effort of digging, the precision of a cut-stump herbicide application, or the slow smothering technique.

Remember, the key is persistence. Attack the plant at the right time of year, dispose of all material carefully, and watch for seedlings. With consistent effort, you can eliminate this invasive grass and restore health and balance to your landscape. Your other plants will thank you for it.