Tree Roots in the Lawn
Tree roots on the surface of the soil can often be unsightly and make mowing and maintaining a uniform lawn difficult. Homeowners often want to know if they can cut them off without damaging the tree. Unfortunately, the answer is a resounding no. Even cutting a small number of roots can open the tree to diseases in the soil, such as root rot. It will also reduce the amount of water and nutrients a tree can take up, leading to stress. Surface roots are caused by poor, compacted soils, shallow, frequent waterings, or by the species of tree. It’s important to remember that most species of trees will have the majority of their roots within the first 2 feet of soil and their feeder roots in the top 8 inches of soil. This is true even in loose, rich soil and with proper watering.
To avoid surface roots in the lawn, some species shouldn’t be planted at all. These include silver maples, sycamores, willows, and American elms. Newly planted trees should be watered deeply and infrequently to reduce the problem in the future. For an established tree that already has surface roots, 2 inches of half compost/half topsoil can be applied over the roots. The area can then be overseeded. This is a temporary solution, however. As roots continue to expand, they will grow through this layer.
Deeper layers of topsoil will smoother the roots and may lead to the tree’s death. Longer-term solutions include mulching around the tree or planting a taller groundcover that doesn’t need to be mowed. Both of these solutions are beneficial to the tree.