How to Kill Weed Trees

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How to Kill Weed Trees

The term “weed tree” can seem like a contradiction, but the truth is trees aren’t always wanted. When a tree begins to grow where it’s not wanted, it’s referred to as a weed tree. Some types of trees are much more common as weed trees because they tend to sprout up naturally (without being planted) and they’re often not the most desirable trees.

Many species in the plant kingdom can act as aggressive invaders if their growth is left unchecked. They can colonize an area by increasing, choking out the nearby trees and plants, preventing their growth and nutrition. To deal with these problems, we have to better understand what these are and then how to kill weed trees.

Related: Best Brush Killers to Master Your Yard

What are Weed Trees?

It sounds like such a funny name, but in fact, it’s not. These are simply the trees that have grown or are growing where they are not wanted, basically like a weed. Well, these trees are not the same as weeds, but they are trees that are larger and harder to remove. Weed trees are generally a species of trees with high germination rates that can grow quickly and subsequently colonize the area in which they’re present. 

How Will You Identify a Weed Tree?

Is the new plant growing on your property a weed tree?

You can find it out by following these simple steps:

  1. Check the stem of the suspected plant. If it is woody (instead of green and soft), then there’s a possibility that it’s a tree. If it has a thicker green stem, then you can rule it out.
  2. Next, take a look at the leaves. The leaves of young trees have the same shape as the leaves on a fully grown tree. You may be able to identify the type of tree by the leaf. You’ll see them on the end of branches instead of growing out from the stem as they do on many other plants.
  3. Take a look at the surrounding area. Most trees grow relatively close to their mother tree. Is there any tree nearby that looks similar? Does it have a similar type of leaves? If so, then you’ve probably found your weed tree.

Some Common Weed Trees

Any unwanted tree can be a weed tree. If a tree is growing too close to your home’s foundation, you might want to get rid of it to prevent potential damage to the foundation caused by the root.  If a tree sapling intrudes in your garden between the planted flowers or vegetable plants, it is a weed tree. Ultimately, it’s not suitable for the home or the tree to be there.

However, there are some types of trees that are more common as weed trees. These are the most common examples of weed trees to watch out for:

1. Norway Maple

Norway Maple Leaves
Norway Maple Leaves

Norway maples are attractive-looking trees that grow to heights of around 40-50 feet. They have dense and rounded canopies, making it difficult or sometimes impossible for the plants growing beneath them to acquire the sunlight necessary for their proper growth. 

Norway maples have leaves that can reach 6 inches in length and 5 inches in width. These leaves are beautiful when they turn yellow in the fall. Despite the beautiful fall color, Norway maples are often weed trees because the wind blows the seeds through the air enabling them to spread in the surrounding areas. This happens with other maples as well, but some maples sprout and grow more easily than others.

2. Silver Maple

Under Side of Silver Maple Leaf
Under Side of Silver Maple Leaf

The silver maple is another tree that can be desirable or undesirable, depending on the situation. They grow to be very tall (50-80 feet) and very dense. Silver maples are easy to identify because the underside of the leaves have a shiny silvery look, which is why they’re called silver maples. As the wind blows through the leaves, you can see the underside of the leaves shimmer in the sunlight.

While silver maples are beautiful trees, they’re also invasive. They have extensive root systems that are very aggressive and can cause damage to underground plumbing, underground utilities, sidewalks, driveways, or anything else that they come in contact with. It’s not recommended to grow a silver maple near your house or anything else that it could damage.

On top of the potential for damage, silver maples also grow very easily. As the seeds spread, they tend to pop up on their own, which makes them a common weed tree.

3. White Mulberry 

White Mulberry Leaves
White Mulberry Leaves

Extensively regarded as a nuisance tree (we can call it a weed here), the white mulberry is originally from China. They have orange-brown bark and sweet, edible berries, which are spread by birds far and away. 

White mulberries adapt and grow in a wide range of conditions and stubbornly develop wherever – even springing new shoots from trees’ trunks or roots. This makes it a tough tree to remove from your yard, garden, or farm.

4. Black Locust

Black Locust Leaves
Black Locust Leaves

The black locust is found in the Appalachian region and the Ozarks of North America. It’s a medium-sized tree with fragrant white flowers in the spring and feathery leaves in collections in summer.

They can grow up to 50 feet with a narrow canopy. They self-seed quite easily and therefore have become an invasive species even in other areas. Once established, the black locust is challenging to control.

Why Kill the Weed Trees?

This has an obvious answer – because they are unwanted. Yes, but let’s discuss the problems caused by these unwanted guests in our yards, gardens, and farms.

First of all, as discussed above, they have a high germination rate. This causes them to grow rapidly, and so they undermine the area required for the intended plants to grow, or they damage the buildings that come in their way.  Due to their presence, the availability of nutrients, water, and minerals decreases considerably, resulting in improper growth of the surrounding plants and trees. 

Weed trees are often quite big compared to the other competing plants around them and they may have a large canopy, which prevents sunlight from reaching the other plants. 

Therefore, it’s essential to eliminate these trees to avoid damage to plants or buildings.

How to Kill Weed Trees

There are a few different ways to kill weed trees. The appropriate and most effective approach depends on the situation, including the size of the weed tree. Here are the approaches you can use.

Killing Weed Trees When They are Still Saplings

The best way to prevent weed trees from becoming a problem in your backyard is to remove them when they’re seedlings. This is the easiest way as it does not require any machines. It can be done quickly by simply using your hands.

Take a look at all areas of your yard or garden and pull any weed trees, just like you would pull a typical weed. If it’s a little too large to pull by hand, there are some other options that are also pretty easy. Mainly, these methods are natural and do not require heavy machinery or work. Also, these methods do not use harmful chemicals, so the quality of soil does not suffer. 

Here are your options:

1. Mowing and Using String Trimming

BLACK+DECKER 20V MAX String Trimmer, 2-Speed, 12-Inch, Cordless (LST522)BLACK+DECKER 20V MAX String Trimmer, 2-Speed, 12-Inch, Cordless (LST522)

The ideal approach to getting rid of weed trees is cutting them or hitting them with a string trimmer. However, this will work only when you do this when they are considerably younger. 

On the off chance that you let them get more extensive, you should cut them by hand. The best part about mowing them is that it kills them and eliminates them permanently.

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2. High Concentration Vinegar

Energen Carolina LLC 578 Vinegar Weed & Grass Killer Approved for Organic Production Pet Safe Glyphosate Free Herbicide, Gallon 1, YellowEnergen Carolina LLC 578 Vinegar Weed & Grass Killer

Using high concentration vinegar to take care of weeds and trees is also a suitable method. 

Most households use vinegar that is at a concentration of 5% weight by volume. However, you can purchase 25% to 30% concentrate and even up to 75% concentrate. These higher concentration vinegars can be used as natural weed killers and cleaners. 

Empty the high concentration vinegar into a gallon sprayer (see our rankings of the best garden sprayers) and shower the leaves of each weed tree. This will most likely get the job done if the weed tree is still a sapling.

Occasionally, yucca extract is added to vinegar. If so, yucca extract can help to give the vinegar a better possibility of killing the tree.  

Most people would prefer to use vinegar over harmful synthetic weed killers to kill weed trees.

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3. Mulching and Weed Barriers

HOOPLE Weed Barrier Fabric, 4 X 150 ft, PP Material, Premium Garden Landscape Fabric for Flower Bed, Yard, Heavy Duty Ground Cover with Green Guide Strip Helps Align Plants, Ultra Thick, Black HOOPLE Weed Barrier Fabric

Mulching is a great way to prevent weeds, including weed trees, from growing and sprouting. Many organic farmers use wood chips and weed barriers.

You will want at least 3-4 inches of wood chips or mulch to keep stuff from growing. When exposed for sufficient time, the heat emitted by the sun will cook off the weeds or trees trying to push up under the tarp because of excessive heat entrapment, successively turning up the temperature around the weed tree.

Related: What To Do With Wood Chips from a Chipper Shredder

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4. Cattle, Goats, and Sheep

This is rather a straightforward approach to killing weed trees, but only if you happen to have farm animals. This can also be used as a method when the trees are in a very early stage. Cattle, goats, and sheep love to make a feast of these young saplings. If you have these animals, allow them to roam where the weed trees are, and they’re likely to take care of the issue.

Related: The Best Weed Killers for Gravel Paths and Driveways

Killing Weed Trees Around 4 Feet or Less

You saw all the methods of killing weed trees in their young state. But what if you are unable to see or figure out the trees at that stage, and they have grown bigger at a stage where the methods mentioned above would not work? Yes, there are methods to deal with them at this stage too. So, let us check them out.

When the trees have grown to an intermediate state, an essential method is treating them with tree killers. Now, what is a tree killer? These are herbicides mixed in gallon sprayers and then sprayed on the weed trees’ leaves. But, this method works only for trees whose height is approximately under 4 feet because, after that, it would take too much of the herbicide to do the job.

Tordon Rtu Specialty Herbicide 1 Qt Kills Woody Plants And Trees Not For: Ca;ny"Tordon Rtu Specialty Herbicide 1 Qt Kills Woody Plants And Trees

Related: What is the Best Weed Killer for Poison Ivy?

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Killing Weed Trees Over 4 Feet in Height

What should you do for large weed trees? Well, there’s an answer for that too. The tree should be cut from the ground level, and then it should be sprayed with tree killers. For example, various tree killers are available on the market.

However, you can also use 2-4 D, Roundup, or high concentration vinegar as well. This will kill the weed tree in about a week. You can also use a black plastic garbage bag to cover up the cut tree’s trunk for this purpose and use duct tape to seal the compartment. This takes a long time, but it is more natural as compared to the above methods.

In any tree, the bark helps to transport water and nutrients to the tree branches and leaves. This makes it an easy-to-reach target to disrupt its growth, thereby giving us the last method, which is called girdling.

Girdling is the process of removing the bark around the outside of the tree trunk. This can starve the tree, resulting in its death. Though girdling is often effective, it might not work all the time. 

Related: Reviews of the Best Weed Killers for Lawns

How to Kill Weed Trees: Final Thoughts

Early identification and removal are the keys to knowing how to kill weed trees. But it’s rarely a one-time problem. If the seeds’ source is nearby, you’ll have to keep on the lookout for more in the future.

If the tree is already well established, then it becomes a more challenging job. Particularly if it already has an extensive root system but can be done to accomplish your landscaping goals or protect structures on your property.

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