In the realm of tree surgery, a root barrier is a crucial tool used to control the growth and spread of tree roots. This term is often used in the context of managing trees in urban environments, where the unchecked growth of roots can lead to damage to structures and infrastructure. A root barrier can be a physical object, a chemical substance, or a method of landscaping designed to limit root growth.

Understanding the concept of a root barrier is essential for anyone involved in tree surgery, landscaping, or urban planning. It is a preventative measure that can save significant time, effort, and expense in the long run. This article will delve into the intricacies of root barriers, exploring their purpose, types, installation methods, and more.

Understanding the Need for Root Barriers

Before we delve into the specifics of root barriers, it is important to understand why they are necessary. Trees, like all living organisms, are driven by a need to grow and expand. Their roots, in particular, are constantly seeking out water and nutrients, which often leads them to grow in directions that can cause problems for human-made structures.

For instance, tree roots can damage sidewalks, driveways, and building foundations, leading to costly repairs. They can also interfere with underground utilities like water and sewer lines. In addition, tree roots can compete with other plants for resources, potentially harming or killing neighboring vegetation. Root barriers are a solution to these problems, providing a way to control root growth without harming the tree.

The Impact of Tree Roots on Infrastructure

One of the primary reasons for the use of root barriers is to protect infrastructure. Tree roots can be surprisingly powerful, capable of cracking concrete and displacing soil. This can lead to uneven surfaces on sidewalks and driveways, creating trip hazards and potentially causing property damage.

Furthermore, tree roots can infiltrate underground utilities, causing blockages and breaks that can be expensive to fix. They can also damage building foundations, leading to structural instability. By installing a root barrier, these issues can be prevented, saving property owners significant time and money.

Competition for Resources

Another reason for the use of root barriers is to manage competition for resources among plants. In a natural environment, trees and other plants compete for water and nutrients, with the strongest and most adaptable species often dominating. However, in a landscaped or urban setting, this competition can lead to undesirable outcomes.

For example, a large tree with an extensive root system can deprive nearby plants of the resources they need to thrive. This can lead to a lack of diversity in plant life, as well as the death of smaller or less competitive species. A root barrier can help manage this competition, ensuring a more balanced and healthy ecosystem.

Types of Root Barriers

There are several types of root barriers, each with its own advantages and disadvantages. The choice of root barrier often depends on the specific situation, including the type of tree, the nature of the potential damage, and the local environment.

The three main types of root barriers are physical barriers, chemical barriers, and landscaping methods. Each of these will be discussed in detail in the following sections.

Physical Root Barriers

Physical root barriers are perhaps the most common type of root barrier. They are typically made of a durable material like plastic, metal, or fabric, and are installed in the ground to block the path of tree roots. The roots encounter the barrier and are forced to grow in a different direction, preventing them from causing damage.

Physical root barriers are often used to protect sidewalks, driveways, and building foundations. They can also be used to create a boundary around a tree’s root zone, preventing the roots from spreading too far and competing with other plants. However, they require careful installation to ensure they are effective and do not harm the tree.

Chemical Root Barriers

Chemical root barriers work by discouraging root growth in a specific area. They typically involve the application of a chemical substance to the soil, which alters the soil’s properties and makes it less attractive to tree roots. The roots are then less likely to grow in the direction of the treated soil, reducing the risk of damage.

Chemical root barriers can be effective, but they also have potential downsides. They can affect the soil’s overall health and may have unintended effects on other plants. They also require regular reapplication to maintain their effectiveness. Therefore, they are usually used as a last resort, when other methods have failed or are not feasible.

Landscaping Methods

Landscaping methods are a more natural approach to root control. They involve designing the landscape in a way that discourages unwanted root growth. This can include planting trees a certain distance from structures, choosing tree species with less aggressive root systems, or creating physical barriers with landscaping features like retaining walls or raised beds.

Landscaping methods can be very effective and have the added benefit of enhancing the aesthetic appeal of the area. However, they require careful planning and may not be suitable for all situations. They are often used in conjunction with other types of root barriers for the best results.

Installing Root Barriers

The process of installing a root barrier can vary depending on the type of barrier and the specific situation. However, there are some general steps that are typically involved. These include planning the barrier, preparing the site, installing the barrier, and maintaining the barrier over time.

Each of these steps is crucial to the success of the root barrier. A poorly planned or installed barrier may not be effective, and could even cause harm to the tree. Therefore, it is often recommended to consult with a professional arborist or landscaper when considering a root barrier.

Planning the Barrier

The first step in installing a root barrier is planning. This involves determining the type of barrier to use, the location of the barrier, and the size of the barrier. The type of tree, the potential damage, and the local environment should all be considered during this stage.

For example, if the tree is located near a sidewalk, a physical barrier may be the best choice. If the tree is in a landscaped area with other plants, a landscaping method may be more appropriate. The size and shape of the barrier will depend on the size of the tree and the extent of the root system.

Preparing the Site

Once the plan is in place, the next step is to prepare the site. This involves digging a trench where the barrier will be installed. The trench should be deep enough to contain the roots and wide enough to accommodate the barrier. Any existing roots in the trench should be carefully cut and removed.

It’s important to note that this process can be disruptive to the tree and the surrounding area. Therefore, it should be done carefully and at the right time of year to minimize stress on the tree. It’s also important to ensure that the trench does not interfere with any underground utilities or other structures.

Installing the Barrier

The barrier is then installed in the trench. If a physical barrier is being used, it is typically placed in the trench and then backfilled with soil. The barrier should be installed so that it is slightly above ground level to prevent roots from growing over the top.

If a chemical barrier is being used, the chemical is typically applied to the soil in the trench. The soil is then backfilled and the chemical is allowed to diffuse into the surrounding soil. If a landscaping method is being used, the landscape features are built or planted according to the plan.

Maintaining the Barrier

Once the barrier is installed, it needs to be maintained to ensure it continues to be effective. This can involve checking the barrier regularly for signs of damage or root intrusion, repairing or replacing the barrier as needed, and reapplying chemical barriers as necessary.

Maintenance is a crucial part of root barrier success. A neglected barrier can quickly become ineffective, leading to the very problems it was designed to prevent. Therefore, anyone who installs a root barrier should be prepared to commit to its ongoing care.


Root barriers are a vital tool in the management of trees in urban and landscaped environments. They provide a way to control the growth of tree roots, preventing damage to structures and infrastructure, and managing competition for resources among plants. By understanding the types of root barriers and how they are installed and maintained, it is possible to make informed decisions about their use.

Whether you are a professional arborist, a landscaper, or a homeowner, a solid understanding of root barriers can help you manage trees effectively and sustainably. With careful planning and maintenance, root barriers can protect property, preserve tree health, and promote a balanced and diverse ecosystem.