Surface Tree Roots – Why They Happen, Can or Should We Do Anything About Them?

You may have experienced this: walking barefoot through your lush grass when, “thump!” you stub your toe on a nasty piece of wood laying low in the turf. Investigating, you see this wood is nothing other than a long, low root annoyingly above the soil line where it doesn’t belong. Why is this root there, and can you remove it?

Surface roots are the normal result of a shallow-rooted tree aging. The primary roots of many trees are within 8 inches of the soil surface. As these roots age they increase in circumference, just like a branch or trunk. The root does not reposition itself below the soil, so the thickening results in part of the root showing up in the turf.

Jeff-WilsonExposed Roots in a Rocky Setting | Photo Catherine Nickelson

Some species are naturally more shallow-rooted than others: Silver and Freeman Maples, Willow, and Linden are those commonly seen in the landscape. These trees are more prone to revealing their roots above the soil line. However, compacted or poorly drained soils can cause many species to produce shallow roots. Compacted or saturated soils are low in oxygen, a necessary element for good root development; trees in these soils will produce roots nearer the surface where there is more available oxygen.

Jeff-WilsonExposed Roots in Turf | Photo Catherine Nickelson

In spite of the inconvenience these roots cause, it is not recommended to intentionally shave them down or remove them. They are active parts of the tree working to stabilize, store energy, and adsorb water. Slicing off significant portions of these roots can stress the tree and impede growth. Also, the roots will immediately attempt to rebuild covering the wound and recreating the issue. In cases of roots threatening to damage sidewalks and pavement a few roots at a time can be completely severed to slow their growth toward the paved surface. This process needs to be monitored and repeated in subsequent years. Great care should be taken in attempting to sever roots; the success of this method is dependent on the size of the roots, nearness to the trunk, and ratio of roots being severed to roots remaining. In general, cutting roots to deal with this problem is not recommended.

Jeff-WilsonExposed Roots in Turf | Photo Catherine Nickelson

There are a couple solutions for the issue of unsightly surface roots. The first is to cover them with a 2-3 inch layer of soil topped with grass seed. The topdressing should be spread evenly across the entire effected area and slope gradually to the existing turf. Soil should not be deeper than three inches as it could suffocate the roots. While topdressing works, it is temporary. The roots will continue to grow in circumference and show up at the surface a few years later. Another solution is to create a mulch bed encompassing all the roots. This bed may need to be extended as the tree grows. A mulch bed serves the additional functions of incorporating organic matter into the root zone and removing the competition for nutrients caused by the grass. Both of these solutions allow you to hide the surface roots, so the tree can remain healthy.

Shallow surface roots can be ugly and annoying in your lawn but they are not an indication of an unhealthy tree. If you like the tree and where it is try to adopt one of the suggested solutions for dealing with the roots. Then, adjust your expectations for that part of your yard and enjoy it as it is.

Catherine Nickelson | Arborist | Horticulturist
Posted 7/30/2021