Seeing tree roots extending along the surface of a lawn is a frequent occurrence. These elevated roots, also called surface roots, are often a natural part of a tree’s growth. Most of a tree’s root system is in the top 12 to 18 inches of soil, where it can access necessary resources. Understanding why these roots appear is the first step in managing them.
Causes of Elevated Tree Roots
The appearance of roots at the soil surface is often a tree’s response to its environment. A primary cause is soil compaction. When soil is dense, it contains less oxygen, which roots need to function. To find adequate oxygen, roots grow upwards toward the surface where the soil is looser and better aerated.
The natural growth habit of certain tree species is another factor. Trees like maples, aspens, and dogwoods are predisposed to having shallow root systems. For these species, visible surface roots are a standard part of their development and not a sign of distress.
Environmental conditions also expose tree roots. Soil erosion from wind and water can wash away topsoil, leaving roots uncovered. Human activity also influences root behavior. Frequent, shallow watering encourages roots to stay near the surface to capture moisture instead of growing deeper.
Potential Issues from Exposed Roots
Surface roots can introduce complications for the property and the tree. For homeowners, exposed roots create an uneven lawn surface, posing a tripping hazard. They also interfere with lawn maintenance, making it difficult to mow without damaging the mower blades or the roots.
Exposed roots are vulnerable to physical injury. Cuts from lawnmowers, string trimmers, or heavy foot traffic can create wounds on the root’s surface. These injuries can serve as entry points for diseases and pests. A damaged root system compromises the tree’s ability to absorb water and nutrients, impacting its health and stability.
Managing Roots at the Surface
When managing surface roots, certain actions should be avoided. Covering roots with a thick layer of topsoil can suffocate them by cutting off their oxygen supply. Another harmful practice is cutting out major roots to level the ground, as this can destabilize the tree and create wounds that invite decay.
An effective solution is applying a 2 to 3-inch layer of organic mulch, like wood chips or bark, over the exposed roots. Mulch helps retain soil moisture, moderates soil temperature, and reduces compaction from foot traffic. As the mulch decomposes, it enriches the soil, creating a healthier environment for the root system and hiding the roots without harm.
Another strategy is to incorporate the roots into the landscape design. Converting the area under the tree into a garden bed with shade-tolerant plants eliminates mowing problems and tripping hazards. Planting groundcovers or other plants that thrive in low light can create an attractive feature that works with the tree’s growth.
Adjusting watering to a deep, infrequent schedule can encourage roots to grow downward. For significant issues, especially near foundations or sidewalks, consult a certified arborist. An arborist can assess the situation and recommend solutions like installing root barriers or performing careful root pruning without harming the tree.