Exposed tree roots are a common landscape challenge that homeowners face. While these exposed root systems are a clear sign of a tree’s age and stability, they create maintenance difficulties, making mowing nearly impossible and presenting a significant tripping hazard. The visibility of these roots is usually a response to soil erosion, compaction, or the tree’s need to access oxygen near the surface. This article provides landscaping solutions that enhance the yard’s beauty without compromising the health of the tree.
Understanding the Limits of Root Coverage
The primary reason tree roots become visible is their need for oxygen, which is most readily available in the top 12 to 18 inches of soil. Applying too much new soil or heavy material over the root zone is dangerous to a mature tree because it suffocates the roots by cutting off necessary gas exchange, leading to decline and death.
Homeowners must strictly limit the amount of material added over the roots to a thin layer, generally no more than two inches of a compost and soil mixture. Adding soil deeper than this creates an environment prone to root rot and encourages the tree to grow new, shallow roots that will eventually become exposed again. Never cut any exposed root that is larger than one inch in diameter, as this can destabilize the tree and open a direct pathway for disease-causing pathogens to enter the vascular system.
Softscaping Solutions Using Plant Material
The safest and most common solution is to create a softscape environment using shallow-rooted, shade-tolerant plant material around the tree’s base. These plants thrive in the competitive, dry, and often shady conditions beneath a mature canopy. The installation must involve minimal soil disturbance to avoid damaging the feeder roots that absorb water and nutrients for the tree.
Preparation should involve a light layer of organic compost, ideally less than one inch thick, spread over the root zone to introduce new organic matter without suffocating the existing roots. Planting should be done using small plugs or bare-root stock, which minimizes the size of the hole needed for installation. Use a hand trowel to carefully excavate small pockets of space between the exposed roots, not directly over them.
Excellent plant choices include species that require very little soil depth and thrive in shade:
- Hostas, which offer varied foliage texture and color.
- Ferns like the Japanese Painted Fern.
- Groundcovers such as Ajuga (Bugleweed) and Epimedium (Barrenwort), which form dense, shallow root mats that compete minimally with the tree.
- Sweet Woodruff (Galium odoratum), which tolerates dry shade and forms a delicate, white-flowering carpet.
New plants will require consistent hand-watering for the first few months until their shallow root systems are established. This dedicated watering prevents the new plants from drawing excessive moisture away from the tree’s feeder roots during the establishment phase. The resulting planted bed eliminates the need for mowing near the trunk and transforms the exposed roots into a textured, natural feature.
Integrating Roots into Structural Design
When softscaping is not desired, non-living materials can be used to manage the root zone safely by creating a functional, integrated design. The simplest method is to establish a wide, organic mulch bed using shredded bark or arborist wood chips, applied in a layer no deeper than three to four inches. This layer cushions the roots, retains moisture, and clearly delineates the area as a non-traffic zone, which is a significant safety improvement.
For creating walkways, consider using permeable paving materials, which are designed to allow air and water to pass through to the roots below. Resin-bound aggregate or specialized permeable pavers can be installed in sections between the roots to form a stable, breathable pathway. This method requires a minimal, non-compacted base layer, ensuring the construction does not seal the soil surface.
The exposed roots can also be incorporated into a design feature by using low, non-restricting elements like a circular bench or a small, elevated retaining wall. These structures should be built around the root zone, not over it, ensuring the trunk’s root flare remains visible and unrestricted. This approach makes the roots part of the aesthetic, drawing the eye to the natural form of the tree while preventing foot traffic from compacting the soil.
Creative lighting can further highlight the root structure, turning the roots into an evening focal point. Small, decorative stones or natural river rock can be used sparingly and between the roots to offer contrast. Care must be taken to ensure the layer remains thin and does not trap excessive heat or prevent gas exchange.