Retaining walls are structures designed to hold back soil or any other materials and prevent erosion. They are commonly used in landscaping to create terraces, level out sloped areas, or create raised flowerbeds. While retaining walls can be both functional and visually appealing, one concern that often arises is whether plants can actually damage these structures. In this article, we will explore the potential damages plants can cause to a retaining wall and provide suggestions on how to prevent or mitigate these issues.
Types of potential damages
1. Structural damage
Plants, particularly trees with extensive root systems, can potentially cause structural damage to a retaining wall. As tree roots grow, they can exert significant pressure on the wall, potentially leading to cracks or even collapse. Depending on the type of retaining wall and its construction material, certain plants may pose a greater risk than others. For instance, retaining walls made of concrete are generally more resistant to root pressure compared to walls made of interlocking blocks or timber.
2. Moisture-related damage
Plants’ natural tendency to absorb water from the soil can also lead to moisture-related damage to retaining walls. When plant roots penetrate the wall, they create points of entry for water. This can result in increased moisture levels behind the wall, leading to potential weakening of the structure. Over time, this moisture can cause the construction materials, such as wood or concrete, to deteriorate or rot.
Prevention and Mitigation
1. Proper plant selection
Choosing the right plants for areas near a retaining wall is crucial in preventing potential damages. Opt for plants with non-invasive root systems or those that have compact root structures. Shrubs, groundcovers, and ornamental grasses are often good choices as they generally have less extensive root systems. It is recommended to avoid planting large trees or plants with aggressive root growth near retaining walls.
2. Create a barrier
To further minimize the risks of plant-related damages, consider installing a root barrier between the retaining wall and the planting bed. Root barriers are physical barriers made of various materials, such as high-density polyethylene or impermeable membranes, that restrict root growth from infiltrating the wall. It is essential to install the barrier at an appropriate depth to ensure roots do not bypass it or cause damage from below.
3. Regular maintenance and monitoring
Regular inspection and maintenance of your retaining wall and the surrounding plants are important for ensuring its longevity. By periodically checking for any signs of damage, such as cracks, bulges, or leaning walls, you can catch potential issues early on and take appropriate measures to address them. Additionally, monitoring the growth of nearby plants can help identify any root intrusion early and prevent further damage.
4. Proper drainage
One way to alleviate moisture-related damage is to ensure proper drainage behind the retaining wall. By incorporating drainage systems, such as gravel or drainage pipes, excess water can be directed away from the wall and reduce the overall moisture levels. This prevents water from exerting pressure on the wall and decreases the likelihood of material deterioration.
While plants near retaining walls can potentially cause damage, taking preventive measures and being attentive to maintenance can greatly reduce the risks. By choosing appropriate plants, installing root barriers, conducting regular inspections, and implementing proper drainage systems, homeowners can ensure their retaining walls remain sturdy and visually pleasing for years to come. With careful planning and conscientious upkeep, plants and retaining walls can coexist harmoniously in any landscape design.