How-to Guide
Exposed Tree Roots in Your Lawn
The short answer
Do not cut or remove exposed tree roots. They are functional roots that take up water and nutrients, and damaging them, by cutting, or by mower and trimmer hits, can seriously affect the tree's health.
Do not bury them under a thick layer of soil. Piling on more than about half an inch of soil can suffocate the roots, because tree roots need oxygen; too much soil over them causes damage or death.
The workable fixes are gentle. Add no more than roughly half an inch of soil at a time if you must, or better, stop fighting the mower: convert the area to a mulched bed a couple of inches deep, or plant a shade-tolerant groundcover into small hand-dug pockets. Keep mulch off the trunk itself.
Why cutting or burying roots backfires
Surface roots that heave up in a lawn are not a defect; they are the tree's feeder roots, doing the job of collecting water and nutrients. Wisconsin Horticulture Extension warns that damaging these roots, whether by hitting them with a mower or trying to prune them away, can seriously affect the health of the tree. Severing a large root also removes support and opens a wound to decay.
The instinctive fix, dumping soil over the roots to smooth the lawn, is just as risky. Wisconsin Extension is specific: apply just enough to cover the roots by about a half inch, because applying too much soil over a tree's roots can suffocate them and cause damage or death. Roots breathe, and a deep, compacted soil cap cuts off their oxygen.
The safe options
If you want to keep grass, add soil only in the thinnest layers, no more than about half an inch at a time, and reseed, accepting that persistent surface roots may simply keep resurfacing. Often the smarter move is to stop mowing over the roots at all.
Wisconsin Extension suggests eliminating the grass and covering the area with a mulch such as shredded wood, or planting the area with a groundcover or perennials in a mulched bed. When planting, hand-dig small planting pockets rather than rototilling, which would shred the roots. Shade-tolerant groundcovers work well under a tree canopy and hide the roots without smothering them.
One caution that applies to all of this: never mound mulch or soil up against the trunk to hide roots at the base. So-called mulch volcanoes trap moisture against the bark and rot the trunk. Keep mulch a couple of inches deep and pulled back from the trunk flare.
Sources
Reviewed 2026-07-18. We cite university Extension, government, and established horticultural sources — and never invent pesticide rates or dangerous treatments.
- Wisconsin Horticulture Extension - How to Deal with Surface Tree Roots — Damaging surface roots by mowing or pruning them can seriously affect the health of the tree; if adding soil, apply just enough to cover the roots by about a half inch because too much soil suffocates roots and causes damage or death; alternatively eliminate the grass and cover with mulch such as shredded wood, or plant a groundcover or perennials in a mulched bed using hand-dug planting pockets.