Using Copper Nails to Kill Trees | Does It Really Work?

You’re right to question whether copper nails can be used to kill trees, is it a myth or does it really work?

In theory, it sounds like a simple, clean, and low-cost plan and I’m not surprised you’re considering it. So to put you out of your misery l can tell you from experience,…it depends.

It depends on several factors, such as the size and to some degree the age of your problem tree. What type of copper nails are used, and how many? Then finally where they are used, so how exactly are you planning to nail them into the tree?

I’ve put together a complete guide to killing trees with nails and will share my first-hand experience of tree removal.

Can You Kill a Tree With Copper Nails

Yes, copper nails can be an effective method of killing small trees. The larger the tree, the less likely this method will be successful.

I have successfully used this technique on deep-rooted saplings, juvenile trees, and dwarf trees. However, the technique involves cutting the tree down to a stump and driving multiple 5-inch nails down vertically into the freshly cut end of the stump.

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How Do Copper Nails Kill Trees?

Once hammered into a tree trunk or roots, the copper will oxidize and release a toxic substance called copper sulfate. Copper sulfate impairs cell production and blocks nutrient pathways leading to the tree dying. Large trees require higher doses, meaning more nails. Therefore this method is most effective for small to medium-sized trees.

To create an effective level of copper sulfate you will need solid pure copper nails, coated steel nails won’t work.

Copper sulfate solutions in their pure form present a risk of toxicity to waterways and to surrounding wildlife according to Purdee University Forestry Dept. Using copper in the form of a nail provides a small controlled dosage directly to the cambium cell layer, the core of the tree responsible for transporting nutrients and fluids.


Copper oxidation is a process where copper, exposed to water and air, corrodes into different copper forms. You may be familiar with oxidized copper if you’ve ever seen green pennies or the Statue of Liberty.

Copper will eventually oxidize into copper sulfate, which can be toxic to people, algae, fungi, plants, and bacteria. However, it is only harmful to people if it is ingested or gets in the eyes, not on the skin.

Stunts Cell Growth

Not only will the copper sulfate be a toxin within the tree, but it actively damages tree cells. The tree can’t continue to grow and keep up with the damage as it binds to and destroys cells.

Leaf Damage

The toxic copper will continue to make its way through the tree, and eventually, it will begin to damage the leaves. They will yellow and whiten, and the tree won’t be able to absorb nutrients from the sunlight due to a lack of chlorophyll.

Root Damage

The best place to position the nails is at the base of the tree near and into the roots. Doing so causes direct physical damage to the roots and opens a pathway for copper toxicity to travel through the tree. Not to mention, it leaves an open wound in the tree that is vulnerable to tree diseases.

Step by Step: Killing a Tree With Copper Nails

Once you accept the limitation of this approach, and the need to apply the nails to a cut stump, it really is just about as quick, simple, and clean a method as you will find. Here are the five simple steps to guide you through the process.

Step 1: Insert Nails Near Base of the Tree

I’ve found it best to hammer the nails into the tree near the base. It helps to get the nails into the roots and deep into the tree.

The larger the nail, the better, both in diameter and length, to cause maximum damage. There’s no standard, but the farther the nail penetrates, the more effective the treatment will be.

If you have a small tree that you have cut down, then drive the nails vertically down into the remaining tree stump, as shown below. I hammered the full length of the nails right down into the stump. Left untreated even a small tree stump like this will put out new shoots or suckers, and begin to grow faster than you may think.

copper nails to kill a small tree stump

Step 2: Insert More Nails To Form a Ring Around the Bark of the Tree

Continue to place nails in a ring, about half an inch apart. The proximity causes maximum damage and higher ratios of copper. It’s a good idea to count how many nails you place to know later when removing them.

Placing the nails around the entire bottom ring of the tree ensures a layer of consistent damage with plenty of copper. It’s especially crucial for big trees.

Step 4: Look Out for New Shoots

Now it’s a waiting game. The time it takes can vary, from 1 to 6 months. The goal here is more of a preventative action. We are aiming to stop the tree from regrowing. So monitor the tree, trimming new growth off for the first month. After one month I would expect no more new strong-looking shoots growing from the remaining stump.

Step 5: Remove the Nails or Dig Out The Stump

Finally, dig out the remaining tree stump and roots. In my backyard, the stumps were located in damp areas of the garden, so I decided to leave the stumps to rot down. I did remove the nails, however, to avoid the risk of copper sulfate adversely affecting surrounding plants, once the stump was rotten.

How Long Does it Take?

Killing a tree with a copper nail is dependent on the size and health of the tree prior to applying the nails.

Generally, small or unhealthy trees will take 4-8 weeks to die. But for larger trees, or trees in more arid locations, it can take up to 6 months.

Will Copper Nails Kill Large Trees?

This depends on what you consider to be large. Copper nails will successfully prevent the regrowth of the tree that has already been cut down. From my own experience trees with a trunk diameter of over 6 inches are unlikely to die as a result of copper sulfate toxification, from the use of nails.

However, placing dozens of nails into the base of mid-sized trees can work, but the process is slow and not very reliable. You can improve your chances of success by removing the old nails, and replacing them with new ones every couple of months.

For larger trees, I would suggest trying the Hack and Squirt method, explain here. In summary, this involves cutting, or ‘hacking’ downward incisions into the tree trunk with an ax. You can then apply a strong herbicide, making sure it drips into the open wounds.

The benefit of this method is that it can be applied to live, standing trees without the need to cut them down. Plus, you can successfully kill large trees, with a high degree of certainty.

Is it Safe To Kill A Tree With Copper Nails?

There are not any practical safety risks, when it comes to using this approach, based on the very low levels of copper sulfate produced. Plus the fact that the chemical is retained within the structure of the tree stump, so it presents no danger directly to the surrounding plant or wildlife.

Copper sulfate is not a health risk to humans when it comes into contact with the skin. However, oral ingestion of concentrated dosage does present a risk, so take precautions if you have children who may be prone to touching the area and putting their fingers into their mouths.

According to the National Pesticide Centre copper sulfate can also act as an irritant if it comes into contact with your eyes. However, using copper nails is very different from using a liquid concentrate. The chances of any copper sulfate residue being produced from the nails and carried at any concentration to human contact are very unlikely.

Other Ways To Kill Trees, Stumps, and Roots

The process of using nails to kill a tree is very simple and low-cost. It is also clean, without the use of chemical concentrates or herbicides.

Still…waiting for up to six months to find out that your 8-inch diameter tree survived your best attempt, may not be an acceptable strategy for you. Some trees can be causing active damage as they grow so removal can’t wait.

No matter how you plan to get it done, there are multiple other ways to kill trees. From other natural methods to commercial-grade herbicides. Here are a few options:

  • The first option is tree girdling. This method removes entire circular chunks of bark around a tree, cutting deep enough to hit the wood. It starves out the roots and stops the tree from producing foliage. You can also pour or inject herbicide into the grooves to speed up the process.
  • If you have a small to medium-sized tree, you can cut it down and cover the remaining stump and roots, with a thick black tarp or plastic sheet. The idea is very simple, you are trying to block any sunlight reaching the remaining stump or tree roots. This is another slow process but may be ideal for areas where having visible black plastic in your yard is not a big issue.
  • If you have a large tree you will probably need to call in professional support to cut it down and remove the waste. You can then set about destroying the remaining stump with a stump grinder, or using the saw and burn technique, both of which I cover in more detail in this article How To Kill A Tree Stump.
  • Applying large amounts of salt to a freshly cut tree stump is another effective technique. Drill holes vertically down into the stump and tree roots directly adjacent to the stump. Pour a few pounds of salt into the area and cover it with plastic to protect the salt from being washed away by rainfall. The salt needs some moisture to penetrate the tree trunk, but make sure there remains a thick salt crust for this to be effective.

Verdict: Using Copper Nails to Kill Trees

So yes you can kill small or juvenile trees using the copper nail method, as long as you apply the nails in the way I have described. It’s not a myth, that’s for sure. But you will need some patience and to be sure of success, you will need to cut the tree down and drive the nails vertically down into the remaining tree stump.

Frequently Asked Questions

Still unsure about using this method for your tree? Check out a few frequently asked questions to figure it all out.