How Much Tordon to Kill a Tree [Application Rates for 5 Methods]

You can kill a tree with as little as one milliliter of Tordon if you use the injection method. However, there are other ways to kill trees with Tordon, and each one requires a different amount. Applying Tordon to cuts in the bark uses more than injection, but is still effective at low rates. Spraying Tordon on the tree bark or leaves uses significantly more Tordon, so these methods should only be used when necessary.

What is the Mixing Ratio for Tordon Tree Killer?

You don’t need to mix Tordon RTU with water or any other ingredient before use. The “RTU” in Tordon RTU stands for “Ready-To-Use.” This means you don’t have to worry about mixing ratios or math. You can use Tordon in all of its many applications without mixing or diluting the herbicide.

All our application rates will be based on this Tordon RTU. We will not be diluting or mixing it with anything, so you can follow these Tordon amounts for yourself.

For all our examples, we are calculating based on a tree that is 24 inches in diameter (60 cm). Smaller trees require less Tordon, while larger trees will require more.

How Much Tordon Should You Use? Every Method Explained

A quick note before we continue: STAY SAFE. Wear work boots, pants, a long-sleeved shirt, eye protection, and breath protection whenever you are handling Tordon or any other herbicide.

1. Tree Injection

“Injecting” Tordon into a tree doesn’t require a needle or syringe. Instead, drill a series of downward-angled holes in a ring around the tree. Then, fill these holes with Tordon. Since you’ll be using a ½-inch drill bit (13 mm) and only drilling holes 2–3 inches deep (5–7.5 cm), it won’t take much Tordon to fill the holes. So, you can use a couple of ounces of Tordon to kill even the largest trees.

For more information on how to perform the tree injection method and others covered in this article, check out our article on how to kill a tree without cutting it down.

Amount of Tordon: 1–2 ounces

2. Cut-Bark Method

The cut-bark method of killing trees with Tordon is similar to the injection method, except it’s faster, easier, and uses a bit more Tordon. Instead of drilling holes in the tree, cut a series of downward gashes in the tree bark, deep enough to expose the wood (I like to use a hatchet for this). Then, pour Tordon directly into the gashes. Use just enough Tordon to dye the exposed wood blue-green.

This method requires about twice as much Tordon as the injection method, but it’s still fairly economical.

Amount of Tordon: 2–4 ounces

3. Basal Spray

If you decide not to cut or drill the tree trunk, you can kill the tree by using Tordon as a basal spray. Simply pour Tordon RTU into a pump sprayer. Then, spray it onto the bottom 12 inches (30 cm) of the tree’s trunk.

Basal spray treatments aren’t always effective at killing large trees, plus it uses significantly more Tordon.

Amount of Tordon: 3–6 ounces

4. Foliar Spray

You can spray Tordon directly on the leaves to kill small trees. Simply add Tordon to a pump sprayer and mist the leaves of the tree. This can require a lot of Tordon, so it’s not a recommended tactic in most cases.

If you can’t reach all the leaves of the tree, don’t try this method. It’s less powerful than other Tordon application routes, so partial foliar sprays don’t usually work.

Amount of Tordon: 6+ ounces

5. Cut-Stump Application

Within 30 minutes of cutting down a tree, paint a ring of Tordon on the top of the stump. The ring should be 1 inch wide (2.5 cm) and cover the outer edge of the stump. This method kills root systems and prevents the tree from growing back.

If your stump was cut more than 30 minutes ago, the Tordon will be less effective. To boost effectiveness, cut off the top 1 inch of the stump. Then immediately apply Tordon. For more info on this method, read our article on how to get rid of tree roots after you cut down a tree.

Amount of Tordon: 1–2 ounces

What Tordon Application Method Should You Use?

Now that you know how much Tordon each method requires, you may be asking which method is the best for you. As a rule, the larger the tree, the less likely it is to be killed by spray applications. Here’s a quick cheat sheet on when to use each tactic:

• Tree Injection: A hyper-effective method that is great for killing very large trees. Best if you are killing a few trees, since drilling holes and filling them can be time-consuming.
• Cut-Bark Method: Great for trees four to 18 inches (10–45 cm) in diameter. Can be used for larger trees too. Since it’s faster than drilling, it’s a good way to kill a cluster of mid-sized trees.
• Basal Spray: Best for trees under 4 inches (10 cm) in diameter. If you’re killing a lot of thickly growing saplings, this method is far faster than slashing and treating every tree.
• Foliar Spray: This is best used for short, shrubby trees and bushes since the Tordon must be sprayed on all the leaves. This makes large-tree applications impossible.
• Cut-Stump Applications: These can only be used on tree stumps. This is an excellent way to kill underground root systems that survived after the tree was felled.

Now, depending on the number and size of the trees you’re killing, you can select the best method for you.

What is the Application Rate for Tordon?

The application rate for Tordon depends on how the Tordon is being used and the size of the tree. The application rates for a 24-inch diameter tree are:

• Injected into the tree: 1–2 ounces.
• Applied to cuts in the bark: 2–4 ounces.
• Sprayed on the bark at the base of the tree: 3–6 ounces.
• Sprayed onto tree leaves: over 6 ounces.
• For freshly cut stumps: 1–2 ounces.

Knowing how much Tordon each application requires allows you to pick the best method for the job. You’ll save money and keep excess herbicides out of the environment by using the proper amount of Tordon each time.