The Best Ways to Kill Leylandii Trees

The Best Ways to Kill Leylandii Trees

Leylandii trees (Cupressus leylandii) are evergreen trees common in residential gardens and landscapes. 

Because of its thick foliage and ability to grow up to 50 feet, it is often used as a hedge to provide privacy to homeowners. 

But just as everything is inevitable to change, there comes a time when you will need to remove the Leylandii tree in your backyard. 

Let’s get to know the best ways to kill Leylandii trees!

How to Kill Leylandii Trees

Cut Surface Treatment

How-To:

  1. Using a chainsaw or ax, make deep gashes as deep as 3 inches on the tree’s trunk.
  2. Spray herbicide onto the cuts until the tree fully absorbs the chemical.

Chemical Injection Method

What You’ll Need:

  • Drill
  • Herbicide

How-To:

  1. Drill 2 to 3 inches deep holes on the trunk up to the tree’s roots. 
  2. Fill these holes with herbicide until it is absorbed. 

Basal Bark Treatment

What You’ll Need:

  • Herbicide
  • Oil-based solvent
  • Portable sprayer

How-To:

  1. Mix 1 part of herbicide with four parts of solvent to achieve a 20 to 25% concentration. 
  2. Ensure that the tree is dry and that flaky barks are removed. 
  3. Spray the solution at the bottom 20 to 24 inches of the tree until it is fully absorbed.

H3: Girdling

What You’ll Need:

  • Hatchet
  • Chainsaw
  • Herbicide

How-To:

  1. Remove a ring about 4 inches wide around the circumference of the tree. Make sure that the ring of the phloem is also removed under the bark.
  2. Spray herbicide on the exposed bark to starve the roots and the tree.

Cutting the Tree Down to a Stump

How-To:

  1. Cut the tree branches and slice the bark, leaving a tree stump behind. 
  2. Drill holes on the tree stump and spray herbicide until the roots fully absorb it.

Using a Foliar Spray

The foliar spray is advisable when you can access and spray on the back of the tree. This process is most effective during hot and calm weather. 

What You’ll Need: 

  • Herbicide
  • Backsprayer
  • Protective gear

How-To:

  1. Wear your protective gear.
  2. Pour the herbicide into the back sprayer. Adding a dye to the herbicide is recommended so you know which part of the tree has been treated.
  3. Spray the herbicide on the leaves of the tree.
  4. The herbicide will now be transported from the leaves to the roots, thereby killing the tree.

How to Kill Leylandii Trees based on Size

How to Kill Leylandii Trees based on Size
Image: Trim Hedge

In sum, here is a table of the most recommended methods to kill a Leylandii tree according to size:

SizeEffective Method
Small Leylandii Tree (8 to 9 feet)Foliar Spray Method
Since small Leylandii trees are grouped as a hedge, the foliar spray method will ensure that all of its leaves absorb the herbicide. 
Large Leylandii Tree (65 to 82 feet)Girdling
By removing a ring of the bark, sugars, amino acids, and other nutrients from the leaves are prevented from reaching the roots and will eventually kill the tree.

Frequently Asked Questions

Can you kill the Leylandii tree with salt? 

Leylandii trees can be killed by regularly pouring salt water near the roots. This will kill the tree slowly but consider the surrounding vegetation to prevent killing them as well. 

How-To:
•Drill a ring of holes at a 45-degree angle at the tree’s base.
•Create a solution with two parts water and one part salt. 
•Pour the saltwater solution into the holes. 
•Fill the holes with mud, and the Leylandii tree will die in a few weeks.
•Apply gypsum on the soil to help it heal from the salting of the dead tree.

When doing this procedure, make sure to be aware of the surrounding plants and grass because contact with the saltwater solution will also cause their deaths.

When is the best time to kill the Leylandii tree?

The best times to kill the Leylandii trees are during the summer and spring seasons. These are the times when the tree’s nutrients are most active, making them easier to disrupt.

Can you kill a Leylandii tree without cutting it down?

You can kill a Leylandii tree without cutting it down through girdling, cut surface treatment, and basal bark treatment. 
See the discussion above to know every step to apply them. 

Are Leylandii trees deep-rooted?

Leylandii trees are deep-rooted, with roots running up to 2 to 3 meters deep. 

Does Leylandii grow back from stumps?

Leylandii trees cannot grow back from stumps. It cannot regenerate from its base, although it may take years before the tree stump will rot away.

Do Leylandii poison soil?

Leylandii damages soil by increasing its acidity level, which leads to the depletion of nutrients. As a result, the soil becomes poor for growing other trees and vegetables.
Leylandii roots extract so much water from the soil that it even causes clay soil to shrink.

How do you stop Leylandii cypress from growing?

To stop Leylandii cypress from growing, prune it regularly. It is generally recommended that Leylandii trees are pruned 2 to 3 times every year.
This way, the hedge’s green shoots and brown areas are trimmed and prevented from shooting new buds that will cause it to grow more.

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