Tordon vs. Roundup: Which is Better for Killing Trees and Stumps?

Tordon is a more powerful tree and stump killer than Roundup, but it is easier to damage surrounding trees and plants when using Tordon. If applied carefully, Tordon can kill trees with less effort than Roundup.

Roundup contains Glyphosate, a non-selective herbicide that is also an effective tree and stump killer. However, effectively killing a tree with Roundup may require drilling holes in the tree or stump and filling them with the herbicide. In comparison, Tordon can simply be painted in a ring along the perimeter of the cut stump. This labor-saver makes Tordon RTU a great choice for clearing brush and trees.

Tordon vs Roundup

What is Better for Killing Tree Stumps: Tordon or Roundup?

Tordon is specifically designed for killing trees and brush, so it handles this task with less effort than Roundup. Simply apply the Tordon around the outer ring of a cut tree stump using a sponge applicator. This Tordon RTU product even contains a colored dye to clearly mark stumps and brush that have been treated.

  • Tordon is a more effective tree and stump killing herbicide than Roundup.
  • Apply Tordon in a 1–2 inch (2.5–5 cm) ring around the outer edge of the cut stump to kill it.
  • Roundup is less powerful than Tordon for killing trees and cut stumps.
  • For best results using Roundup to kill stumps, drill several 1–2 inch (2.5–5 cm) deep holes in the stump and fill them with Roundup.

Because Roundup is not specifically designed for battling trees and brush, using it as a stump killer requires more effort. This includes drilling 1–2 inch deep holes around the outer ring of a cut stump and filling them with Roundup. This treatment is required to ensure the herbicide is absorbed by the tree. Also, Roundup is colorless. Without the dye found on most Tordon RTU products, you make lose track of where you have and haven’t applied Roundup when clearing brush.

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How Long Does it Take for Tordon to Work vs. Roundup?

Both Tordon and Roundup require 7–14 days to fully kill whatever tree or stump they have been applied to. Because of the similar timelines for effectiveness, there is not a clear winner here.

  • Tordon and Glyphosate both require 7–14 days to fully kill a tree.
  • Reapply Tordon after 10 days if you do not see results.
  • Reapply Roundup after 14 days if the tree is showing signs of continued growth, such as green sprouts from roots or cut trunk.

Both Tordon and Roundup may require reapplication to kill trees and brush. If a tree is still green, or if the cut tree continues to send forth new sprouts 10–14 days after application, perform a second treatment.

Will Tordon Kill Surrounding Trees?

Tordon can kill surrounding trees in the area of application, even if the the tree was not directly exposed to the chemical spray. This is because Tordon enters the soil by penetrating the stump of the treated tree and spreading to the roots. Once there, it may “jump” from the treated tree’s roots to another tree’s roots.

  • Tordon remains active in the soil for 90 days.
  • Tordon can kill trees that were not directly exposed to the product.
  • After it is applied to a cut stump, Tordon penetrates to the root zone of that tree. Tordon can then attack other tree roots in the soil, killing nearby trees.
  • Do not use Tordon if the tree to be killed is planted near desirable trees.

Because Tordon is persistent in soil and can kill nearby trees with herbicides, it is best used to kill isolated trees or to clear brush from areas. Tordon is not a good option for killing one unwanted tree growing among other trees you wish to keep alive.

Will Roundup Kill Surrounding Trees?

Glyphosate, the active ingredient in Roundup, will only kill plants that were directly exposed to the herbicide. This is because Roundup is not active in soil and cannot be transmitted from trees to another plant growing nearby.

  • Roundup is much safer for nearby plants than Tordon.
  • Only plants whose leaves or cut stump were sprayed with Roundup will be attacked by the chemical.
  • Once in the soil, Roundup bonds with clay particles, making it harmless to other plants.
  • Use Roundup to kill single trees growing near desirable trees and bushes.

If you perform proper stump treatment with Roundup and do not spray surrounding plants directly then a Roundup application will leave nontarget plants and trees unharmed, while killing target plants down to the root.

Is Tordon Safer than Roundup?

Tordon remains active in the soil for up to 90 days, making it far more lethal to nearby plants than Roundup. However, Glyphosate, the active ingredient in Roundup, has been at the center of controversy due to its links to cancer in humans. Tordon has never been shown to be toxic to humans.

  • Tordon remains active in the soil for 90 days at regular doses. It can attack the roots of existing or newly planted trees and bushes during this time.
  • Glyphosate (Roundup) is not dangerous to other plants after it has entered the soil.
  • No link has been found between Tordon exposure and cancer in humans.
  • Glyphosate exposure has been linked to non-Hodgkins Lymphoma, according to studies.

It’s key to know the risks before using a chemical herbicide. Although both Tordon and Roundup are classified as safe by the EPA, there is more reason to be cautious about exposing yourself to Roundup than Tordon.

Does Tordon Leach Into Soil?

Tordon will leach into the soil after application to tree bark or a cut tree stump. This is because Tordon penetrates to the root, where it can then move from the tree roots into surrounding soil.

  • Tordon will leach into the soil from the roots of a treated tree. From here, it can harm other trees.
  • Glyphosate will not leach into the soil. Once it has entered a plant, it will not migrate to another plant.

Glyphosate will not leach into the soil and continue to kill plants. This makes it a much more easily controlled option for killing trees with herbicides.

How Long Does Tordon Stay in the Ground?

Tordon’s half-life in soil is 90 days. However, if applied to an area at high volume, Tordon may remain in high enough quantities to harm trees and bushes for 2–3 years. To avoid this, use Tordon according to product label instructions and rates.

  • Tordon remains active in the soil for up to 90 days.
  • If an excess of Tordon is applied, it may remain active for 2–3 years.
  • Roundup remains in the soil from 3–249 days, depending on soil type and watering frequency.
  • Once in the soil, Roundup is inert and will not harm plants.

The root zone of a tree treated with Tordon is toxic to trees and brush for the following 90 days. In comparison, Roundup is rendered inert by soil. You are free to plant in an area treated with Roundup spray after 3 days.

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Which Should You Use to Kill a Tree: Tordon or Roundup?

Tordon is more effective and more easily applied than Roundup, but there is a much higher risk that Tordon will leap from the treated tree’s roots to attack nearby trees. If you want to keep nearby trees safe, use Roundup.

  • Use Tordon to clear brush and kill isolated trees.
  • Tordon is best for killing hardy trees and brush.
  • Use Roundup to kill unwanted trees growing near desirable trees and bushes.
  • Roundup application to a cut stump takes more work than Tordon, but keeps nearby plants safer.

Tordon RTU is designed to be a brush and tree killer, and contains a dye that makes working with it easier than Roundup. For big, tough jobs, Tordon is best. For delicate work in your yard and garden, Roundup is the superior tree killer.

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