How To Stop Tree Roots From Growing Back (3 Expert Tips)

In several ways, overgrown tree roots are a costly prospect for any homeowner. Damage to foundations, pipes, and paths creates severe safety issues alongside complex repairs. With tree root damage often running several thousands of dollars, cutting down the tree is usually the only cost-effective solution.

The trouble is that roots don’t go away without a fight, and while you may momentarily stop them by dropping the tree, it won’t take long for certain species to continue their outward growth. If roots are threatening your property, preventing any chance of regrowth is crucial for your safety, comfort, and convenience. Keep the problem away for good with these three expert tips to stop tree roots from growing back.

The 3 Tips to Stop Tree Roots From Growing Back

1. Apply Systemic Herbicides to Tree Stumps

Systemic herbicides keep tree roots from coming back by targeting them specifically. Unlike contact herbicides, which only kill the parts of the plant they touch, systemic herbicides travel through the tree’s phloem, which is the vascular layer that transports photosynthesis products to the rest of the tree.

For killing tree roots, experts recommend solutions containing at least 20% glyphosate or 8.8% Triclopyr. These solutions work on still-living stumps, with glyphosate halting protein production and Triclopyr acting as a growth regulator.

Imazapyr is another highly effective product that roots readily absorb. Most imazapyr solutions are for commercial use only, as they have higher soil activity and last longer in the soil than other systemic herbicides, putting nearby desirable plants at risk.

Use Systemic Herbicides Quickly

In many cases, systemic herbicides kill trees and roots faster if the tree is still standing because they absorb through the plant’s leaves. If you find suckering on a recently cut tree, apply herbicide before removing the sucker.

Systemic herbicides work best if you use them within minutes after cutting down the tree to prevent root regrowth from tree stumps. Stumps begin healing and sealing themselves from harm quickly, and immediate application will ensure they still readily absorb the herbicide. If the stump has been sitting for a while, you’ll need to cut a new slice to expose fresh wood before spraying.

How to Use Systemic Herbicides

Cut the stump as close to the ground as possible. Keep the cut at an even horizontal angle to prevent your liquid herbicide from rolling off. Spray the stump with herbicide.

For girthier trees, concentrate the spray on the outer edge where the bark meets the tree’s inner rings. The still-living stump will continue transporting the herbicide through its phloem. If the tree is only a few inches wide, you can cover the entire top of the stump.

Wear protective gloves and face coverings while working with a spray herbicide. Do not apply on windy days or when you expect rain within the next several hours. Although glyphosate and Triclopyr break down fast and have low soil activity, they may drift to nearby plants.

To reduce the risk of drifting herbicide, use a paintbrush to apply it to the tree. Herbicides will start to take effect in about 2–3 weeks, though larger tree root systems may take slightly longer to die.

2. Kill the Stump with Salts

Tree roots stop growing after you cut off their food supply from the leaves. But resilient and troublesome trees, such as poplars and elms, will still pull nutrients and moisture in with the root system, often successfully fueling the emergence of shoots and suckers from the stump or exposed roots. By depriving the roots of moisture, you can prevent sucker formation and accelerate stump decay.

Various salts can kill the stump and roots, with Epsom salt and rock salt being two popular solutions. Epsom salt helps plants to a degree, but an excess will limit vital nutrient uptake, making it harder for the roots to produce suckers. Both salts dry the tree out, preventing moisture from carrying nutrients and eventually killing it.

How to Kill a Tree Stump with Salts

Choose a day when the weather is warm with no rain in the forecast. An already dry stump will be easier and faster to kill. Drill inch-wide holes in the top of the tree stump, spacing them about 4 inches apart and drilling them 4–12 inches deep. Next, cut inch-wide holes at a downward angle into the side of the stump. You can also cut holes into any exposed tree roots.

Fill each hole almost full of Epsom or rock salt. Pour water into the holes to help the salt absorb into the stump, taking care not to overflow them. While these solutions are unlikely to hurt nearby plants in small amounts, it’s essential to reduce unwanted contact.

After the application, cover the stumps with plastic sheeting or tarps to keep wind and weather from displacing your stump killers. Epsom salt and rock salt may take several applications every 1–2 weeks, but you should see the stump die and rot within about 6–12 months.

3. Remove the Stump

After drying out and killing the stump and roots, you can remove them to ensure tree roots won’t grow back. You have a few options—tear the tree out with a winch, grind it down, or burn it out. These options can also work for a fresh-cut and still-living trunk.

Stump Grinding

A stump grinder costs about $250–$300 to rent for a day, but you may want to hire a professional due to the challenges and hazards. Because it doesn’t remove the stump completely, there is still a slight chance that tree roots could grow back.

Pull Out the Stump

Whether the stump’s dead or alive, a winch is the fastest way to pull it out. You’ll have to dig down a few feet to expose and sever the roots with an ax or chainsaw before removing the stump. Once separated, the stump can hook up to a winch or a truck for you to force out. After pulling out the stump, you can go the next step in stopping tree roots from growing back by painting the cut ends with an herbicide before refilling the hole.

Burning the Stump

Burning the stump requires the most preparation due to the danger. Consider municipal laws for outdoor fires, the stump’s proximity to your house and other structures, and the weather. Drought, dry conditions, and high winds can be extremely hazardous when burning.

Dig around the stump to expose as many roots and wood as possible. Bore holes into the wood as you would for Epsom salt, drilling several across the top and at downward angles on the side. Then, pour kerosene into the holes, which will penetrate the wood over the next 24–48 hours, or fill them with potassium nitrate and water.

The active ingredient in stump killers like Spectracide Stump Remover is potassium nitrate (or saltpeter), which will expedite decomposition. The stump will rot in a few weeks, making it easy to remove. The saltpeter, an essential gunpowder component, soaks into the wood as water dissolves it. Though it isn’t combustible, it’s a powerful oxidizer that will accelerate the burn when you’re ready to torch the tree stump.

Clear away any brush from the tree stump before burning. You can take extra precautions by soaking the perimeter with a garden hose and keeping it wet during the fire, which can take up to 24 hours or even longer to finish. After igniting the stump, drill horizontal holes into the side to meet the downward holes for better airflow.

You’ll need to monitor the stump during and after the fire. Roots may continue smoldering, creating unexpected flames further away from the original fire.

How Can I Stop Roots From Damaging My Foundation?

Long-time homeowners often develop a deep attachment to the natural features that have defined their property for years, and cutting down a tree that almost feels like part of the family can take an emotional toll. But when encroaching roots threaten the house, you have to take action.

Fortunately, there is a middle ground where protecting your home and saving the tree go hand-in-hand. A root barrier is a structural or chemical wall under the soil that stops tree roots from reaching plumbing and foundations. Trap barriers allow roots through but girdle them to hinder growth.

Structural and Chemical Root Barriers

Lasting indefinitely, solid root barriers consist of concrete, plastic, or metal. The walls go at least three feet into the ground, typically extending 1 foot below the home’s foundation. Ridges and lips on the root-facing side prevent roots from moving around the structure.

By contrast, a chemical barrier is a mesh with an herbicidal treatment, such as Trifluralin, that stops root growth at the tips, generally without affecting nearby vegetation. These solutions only last about 3–5 years before needing retreatment.

The best root barrier depends on several factors, including your soil structure, the home’s proximity to the tree, and the regional climate. Working with a professional installer is critical. Improper setup can cause a root barrier to fail or kill your tree. At about $60–$65 per downward linear foot, expansive root barriers are often pricey but still far more preferable to spending $3,000+ to repair a broken pipe or basement wall.

Does Homeowners Insurance Cover Tree Root Damage?

Stopping tree roots from returning is critical if they threaten your home, as repairs for broken sewer pipes, underground utility lines, and foundations can get pricey. Minor fixes may only set you back $100–$200, but severe damage can cost a few thousand dollars. And unfortunately, the repair costs will be yours to bear.

Homeowners insurance won’t cover tree root damage because of its gradual growth, which you may have been able to prevent. Insurance covers sudden loss due to covered perils, and since the roots didn’t cause the damage in an instant, providers see it as neglect. If the tree damages plumbing that leads to a burst water pipe in the basement, your insurer will cover the water damage because it was sudden. The pipe and tree root, however, will be up to you.

Conclusion

Tree roots are determined to stay alive no matter how hard you wear them down. Killing them off can become an unexpected challenge and a recurring headache as you find new shoots weeks after felling a tree. If a tree is putting your home at risk, following these safe and simple tips will deliver a fast and permanent solution.

Featured Image Credit: Ninadoiron, Pixabay