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You can kill crepe myrtle roots by cutting off their access to water, applying targeted herbicides, or physically removing the entire root system.
But here’s the thing—crepe myrtle roots are stubborn, and just cutting down the tree or drilling into the stump often triggers aggressive regrowth from the remaining root network.
If you’ve been asking how do you kill crepe myrtle roots because you’re tired of new shoots popping up everywhere, you need a solid plan that attacks the roots directly.
In this post, I’ll break down the most effective methods to kill crepe myrtle roots, the tools you’ll need, and the common mistakes that keep these roots coming back.
Let’s dig in.
Understanding How Do You Kill Crepe Myrtle Roots Effectively
The first step in learning how do you kill crepe myrtle roots is understanding why they’re so resilient.
Crepe myrtles have a fibrous, sprawling root system that spreads wide but stays relatively shallow.
This network of roots stores energy, and as long as any part of that system remains alive, the tree will try to regenerate.
So killing crepe myrtle roots isn’t about just hacking at what you can see; it’s about starving the entire underground system.
Here are the most reliable ways to kill crepe myrtle roots for good.
1. Starve the Roots by Removing the Canopy
One of the simplest ways to kill crepe myrtle roots is to cut the tree down completely and remove all visible growth.
When you kill crepe myrtle roots by removing the canopy, you cut off the leaves that produce food through photosynthesis.
Without that energy supply, the roots will eventually run out of stored starches and die.
However, this method takes patience because the roots can survive for months or even years on stored energy.
To speed things up, you’ll need to combine this with another method, like herbicide application.
2. Apply a Strong Herbicide Directly to the Cut Stump
If you want to know how do you kill crepe myrtle roots fast, the answer is almost always a herbicide.
After cutting the trunk down to a few inches above the ground, immediately paint the freshly cut surface with a glyphosate or triclopyr concentrate.
The cut surface is like an open wound, and the herbicide gets absorbed directly into the root system.
You need to apply the herbicide within 30 minutes of cutting, because the wound seals over quickly.
This is the most effective way to kill crepe myrtle roots because the chemical travels down to the entire root network.
For thicker stumps, drill several holes into the top and pour the herbicide into those holes for deeper penetration.
3. Use the Drill-and-Fill Method for Older Trees
For mature crepe myrtles with large root systems, the drill-and-fill method works wonders.
Drill vertical holes into the stump, spacing them about an inch apart.
Then fill those holes with concentrated herbicide, which seeps down into the roots.
This method is highly targeted, and it allows you to kill crepe myrtle roots without harming nearby plants.
Be careful not to spill the herbicide on surrounding grass or flower beds, as it will kill those too.
You’ll know the herbicide is working when you see the stump and roots start to dry out and crack over a few weeks.
Physical Removal Methods to Kill Crepe Myrtle Roots
If you don’t want to use chemicals, you can kill crepe myrtle roots by physically digging them out.
This is hard work, but it’s the only guaranteed way to remove the roots permanently.
Here’s how you can do it effectively.
1. Dig Out the Root Ball Completely
Start by digging a wide circle around the stump, about two to three feet away from the base.
Use a sharp shovel or a mattock to loosen the soil and expose the main root ball.
Crepe myrtle roots tend to grow shallow and wide, so you’ll find most of the mass within the top 12 to 18 inches of soil.
Cut through any thick lateral roots with a root saw or an axe.
Once you’ve severed the main roots, you can pry the entire root ball out of the ground.
You’ll need to kill crepe myrtle roots by removing every piece, because even a small root fragment left behind can sprout a new tree.
2. Rent a Stump Grinder for Large Stumps
If the stump is too big to dig out by hand, renting a stump grinder is your best bet.
A stump grinder will chew the stump and the upper portion of the roots into sawdust.
This won’t kill crepe myrtle roots that are deep underground, but it removes the bulk of the root mass.
After grinding, you can apply a herbicide to the remaining exposed roots to finish the job.
This combination—grinding plus herbicide—is a surefire way to kill crepe myrtle roots quickly.
3. Smother the Roots with a Tarp
For a natural, chemical-free approach, you can kill crepe myrtle roots by smothering them.
Cut the tree down as low as possible, then cover the entire area with a thick, opaque tarp.
Weigh down the tarp’s edges with rocks or bricks to keep it in place.
The tarp blocks sunlight and water, which starves the roots and prevents any new shoots from emerging.
Leave the tarp on for at least six months to a year to fully kill crepe myrtle roots.
This method is slow but very effective, and it’s perfect for gardeners who want to avoid chemicals.
Why You Might Not Want to Kill Crepe Myrtle Roots
Before you go through all this trouble, it’s worth asking yourself if you really need to kill crepe myrtle roots.
Crepe myrtles are prized for their beautiful summer blooms and attractive peeling bark.
If your tree is healthy and not causing problems, you might want to keep it.
However, you should kill crepe myrtle roots if they’re invading your septic system, cracking your driveway, or interfering with your foundation.
Crepe myrtle roots are also notorious for sending up suckers from lawns, which can be a real nuisance.
If you’ve tried pruning the tree back and it keeps coming back stronger, that’s a sign that you need to address the roots directly.
Common Mistakes When Trying to Kill Crepe Myrtle Roots
Many homeowners fail to kill crepe myrtle roots because they make one of these common mistakes.
Avoid these errors so you don’t waste your time.
1. Just Cutting the Trunk Without Herbicide
Cutting a crepe myrtle down to a stump doesn’t kill the roots.
In fact, it often makes the problem worse by triggering a burst of suckers from the base.
You must combine cutting with herbicide or physical removal to actually kill crepe myrtle roots.
2. Using Diluted Herbicide
When you kill crepe myrtle roots with chemicals, you need to use a concentrated solution.
Diluted, ready-to-spray weed killers won’t have enough strength to reach the deep roots.
Always read the label and use the highest concentration recommended for stump treatment.
3. Removing the Stump Too Early
After applying herbicide, you need to leave the stump alone for several weeks.
If you try to uproot or burn the stump too early, you might not have killed crepe myrtle roots yet, and they’ll survive.
Wait until the wood is spongy and soft, which indicates the roots are dead, before you try to remove it.
So, How Do You Kill Crepe Myrtle Roots?
You can kill crepe myrtle roots by using a combination of cutting, herbicide application, and physical removal.
For the fastest results, cut the tree down, apply a concentrated herbicide to the fresh stump, and then wait a few weeks.
For a chemical-free approach, dig out the root ball entirely or smother the area with a tarp for a year.
The key is to be persistent and thorough, because crepe myrtle roots are tenacious.
I hope this post has given you a clear path forward on how do you kill crepe myrtle roots, so you can finally reclaim your yard from these stubborn invaders.
Good luck with your project, and may your garden be free of unwanted root sprouts.