Will Roundup kill pines, is a valid question because despite being pretty, pines’ invasive root systems can become problematic in your garden. Luckily, Roundup is a potent herbicide that can kill young and mature pines in your garden.Roundup Kill Pines

Our gardening team will tell you everything about using this product, so read on to know all about them.

Will Roundup Kill Pines?

Yes, Roundup kills pines when they are small and mature trees. When uprooting a pine tree isn’t an option, you can also utilize it if you need to kill the tree. This non-selective herbicide will kill all plants, flowers, shrubs, and trees it contacts, including pines.

Roundup contains an active ingredient called glyphosate, and it blocks the enzyme pathways in the tree, making it unhealthy and eventually killing it if applied regularly. Using this product will prevent the essential proteins from forming, affecting the growth of any plants it touches. However, to kill a pine, you must apply this chemical regularly, as it takes longer to kill a pine tree.

– Functionality

The glyphosate in Roundup will destroy weeds in your lawn and can also kill the lawn itself. It blocks the formation of proteins, so it kills various plants upon contact. People usually apply it to the foliage, where it stunts growth. However, if you are aiming to get rid of pines in your garden, apply Roundup to the tree roots. This way, Roundup can travel through the vascular system of your pine, eventually killing it.Destroying Weeds from Garden

Glyphosate can be absorbed through the tree’s foliage, trunk, and roots, so you can use both methods to kill the stubborn pines. Roundup shows faster results on seedlings and young trees. However, in the case of mature pine with an extensive root system, it will take several applications and more time to kill your pine.

So, whether it travels from the foliage to the roots or from the root system to the leaves, Roundup will eventually inhibit the absorption of necessary nutrients. Although you can apply Roundup directly on the tree’s bark, this is the least potent method. It takes more time and more frequent application, so you’ll end up using more of this product to get rid of pines.

– Duration

This depends on the tree’s age and size. For most weeds, plants, and shrubs, glyphosate takes between seven and 14 days to kill trees, so you can see the damage on a young pine during this period.

For mature pines with extensive root systems, you’ll need several applications. It may, at timese, take up to six months to eventually kill mature trees like pines. You can start applying this product in the summer and fall. However, some trees will show real damage in the spring.

– Composition

This gardening chemical is one that contain imazapyr or imazapic will remain in the soil because they’re water-soluble. They act as non-selective herbicides and will kill weeds, grass, plants, shrubs, and trees upon contact. However, the degree of concentration determines which trees will be affected by this herbicide. As a result of this, you can also try to use it to treat weeds and unwanted plants in your garden, but it won’t affect southern pines.Eliminating Trees with Roundup

Although Roundup is an excellent product for eliminating trees that compete with other plants for food and also for water, which is why you can also use it to eliminate unwanted weeds and plants that grow in several areas of your garden.

If you want to keep various trees in your landscape but want to eliminate the weeds that grow under them, you need to use diluted Roundup and ensure you’re spraying it away from the trees’ root systems. It’s also important to avoid using Roundup on a windy or rainy day to prevent the product from flying in the air and water and landing on the tree’s foliage or roots.

For this purpose, you can create a wind barrier around your tree using fleece or any other material to limit the unwanted effects of Roundup. Use a gardening spray Roundup at the lowest setting to prevent the spread of Roundup to unwanted areas in your garden.

How Does Roundup Kill Pine Trees?

Roundup kills pine trees as glyphosate substance gets into the tree’s vascular system. When it is injected at least one milliliter into each hole, you cut into the tree’s bark to kill a mature pine. Injecting more will accelerate the process of killing pine trees in your garden.

In addition, you can spray it at the roots or on the tree’s suckers, where it travels through the tree’s internal system. Applying this substance depends on the size and age of your pine. Roundup is toxic to various wildlife forms, including birds and beneficial insects in your garden, so, applying it to plants’ foliage for pest infestation can do more harm than good.

– For Small Trees

Applying Roundup to the foliage will work if you have a pine that measures shorter than four feet tall. Before application, you should wear protective gloves and goggles, as you’ll use the chemical without dilution.Applying Roundup on Small Trees

Ensure the leaves are clean and free of frost and dust to guarantee better absorption. Use a powerful hand-held sprayer with the highest concentration possible and apply Roundup to the foliage. Make sure that you cover the leaves from all angles.

It’s best to apply Roundup in mid to late summer when the leaves are fully grown to ensure better coverage. The results can show immediately, or some time might pass until the foliage starts wilting. Some trees might show foliage damage in the spring.

– For Mature Trees

Mature trees need more Roundup that should be directly injected into the tree’s vascular system. This is why you should make holes into the tree’s bark to inject Roundup directly into the vascular system.Mature Trees in the Garden

Before applying this chemical, you should wear protective gear to protect yourself from chemical contact. Drill several half-inch diameter holes, making sure that these holes are at least 3 feet above ground level.

Holes should be drilled at a 45-degree angle and should be at least one inch deep. This allows the chemical to travel to the roots and other parts of the tree. Use a garden sprayer to fill each hole with the potent herbicide.

Instead of waiting until your tree absorbs this product, you’ll directly inject it into the vascular system. In most cases, mature pines will take between six weeks to a maximum duration of of six months, and they will die completely. If this sounds too much of work, you can use an axe to make many cuts in the tree’s trunk. This way, the potent chemical will get into the cambium layer and directly reach the vascular system to kill the tree from the inside.

Killing trees is also possible by cutting down mature trees and applying Roundup to tree stumps. Once this tree has died, you can apply Roundup to the remaining stump to poison it. Tie a plastic bag around the remaining stump to prevent water and sunlight absorption. Add some bricks to weigh the plastic bag down, and the stump will die within 3 to 6 months.


Roundup is a potent non-selective glyphosate herbicide that can be used to eliminate unwanted weeds and pines that deprive nearby plants of nutrients and water, so remember:

  • Roundup contains glyphosate, which deprives plants of forming certain proteins.
  • Roundup shows faster results on younger trees than mature pines.
  • It takes several weeks to kill young pines but several months to affect older pines with extensive roots.
  • To treat weeds in your garden, you can use diluted Roundup on a dry day to prevent accidental contact with nearby trees and shrubs.

Even long-living pines won’t tolerate being exposed to these chemicals, which is why if you are looking for herbicide that won’t kill pine trees this is not the choice.

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