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Wondering how to fix exposed tree roots in lawns are one of those problems that seem to have an obvious fix — until you find out the obvious fix can kill your tree. I’ve got two big trees in my front yard, and their roots snake up through the grass, catch the mower deck, and make the whole yard a pain to cut. My first thought was the same one most homeowners have: buy some dirt, cover the roots, and level it all out.
My wife stopped me before I made the mistake. As it turns out, burying tree roots is one of the fastest ways to slowly kill a healthy tree — and I would have learned that the hard way. Here’s what actually works, what to avoid, and how I ended up handling it in my own yard.
Why you should never just bury exposed tree roots with dirt
Here’s the part almost nobody knows until it’s too late: tree roots grow near the surface because that’s where the oxygen is. The feeder roots that keep a tree alive live in roughly the top few inches of soil, and they need to breathe. When you pile a thick layer of dirt over them to smooth out your lawn, you cut off that airflow.
The tree may look fine for a season or two, then slowly decline — thinning leaves, dead branches, and eventually a tree that has to come down. Certified arborists and university extension programs are nearly unanimous on this point: covering exposed roots with more than about a half inch of soil is a mistake, and a raised bed of dirt packed over the root zone is worse. The roots didn’t come up to annoy you. They came up to survive.
What actually causes exposed tree roots in lawns
Understanding the cause helps you pick the right fix. Most of the time, exposed roots aren’t the tree “pushing up” — it’s the soil around them washing or wearing away. Rain and runoff erode topsoil, foot traffic and mowers compact what’s left, and shallow-rooted species make it worse. Maples, willows, sycamores, and some ash and beech trees are notorious surface-rooters.
On top of that, grass struggles to grow under a shade tree because it’s competing with the tree for both light and water — a mature tree can drink up to a hundred gallons on a hot day — so the turf thins out and the roots get even more exposed. That’s why “just grow thicker grass over them” almost never holds: the roots will win that fight every time.
The best fix: build a mulch bed over the roots
The single most recommended solution — from certified arborists to university extension offices — is also the easiest: turn the problem area into a mulch bed. Instead of fighting the roots with your mower every week, you stop mowing there entirely and let mulch do the work. Clear the thin, struggling grass from between the roots by hand (don’t use a weed trimmer or herbicide right on the roots — both damage them), then spread two to three inches of shredded hardwood bark mulch over the root zone, ideally out toward the tree’s drip line.
Keep the mulch pulled a few inches back from the trunk itself — never pile it against the bark in a “mulch volcano,” which traps moisture and rots the tree from the base up. A natural, dye-free hardwood mulch is the right choice here; the roots can breathe, water still gets through, and the whole area looks intentional instead of ragged.
One honest heads-up on quantity: mulch beds around mature trees cover more ground than people expect, so a single bag usually won’t finish the job. Measure your bed before you buy so you’re not making three trips. Our mulch calculator can tell you exactly how many bags or cubic yards you’ll need for the area and depth you’re covering.
What I did in my own yard
Not every yard suits a full mulch bed, and mine was a mixed case — I wanted to keep some lawn between the two trees but stop tripping the mower on the worst roots. So instead of burying the roots, I worked around them. When I dug out the flower beds along the house, I saved all the sod and soil that came up, and I used it to gently build up the low spots between the roots — filling the valleys, not covering the ridges.
The tops of the roots stayed exposed to the air, which is exactly what keeps them healthy, but the ground between them got closer to level, so the mower rides over instead of slamming into them. It’s the same principle the arborists recommend: you can add a little loose material around roots to smooth the walking and mowing surface, as long as you never smother the roots themselves.
Cutting small roots: only if you have to, and at your own risk
Sometimes one stubborn root sits high in a spot where a bed won’t work. Cutting is possible, but it’s genuinely risky, and the consensus among tree professionals is to avoid it when you can. If you decide to cut, the safe limits are narrow: only small roots — think smaller than your thumb, and no more than a couple inches thick at the very most — and only well away from the trunk, never the big structural roots near the base that anchor the tree. Cutting a large or close-in root can destabilize the tree, open it to disease, and in a storm, put the whole tree on the ground.
A folding hand pruning saw gives you the control to make a clean cut on a small root; after cutting, fill the hole with soil, seed it, and water it. If there’s any doubt about a root’s size or how close it is to the trunk, stop and call a certified arborist — that call is far cheaper than replacing a mature tree.
Shaving a root down: the advanced option (read this carefully)
There’s one more technique some experienced landscapers use on a root that’s too big to cut but too high to mow over: shaving the very top of the root down with an electric hand planer, rather than cutting through it. Done carefully, it lowers the high point without severing the root. But understand the risk clearly — this wounds the root’s protective bark and opens it to rot and disease, and most certified arborists do not recommend it as a DIY fix.
If you choose to try it anyway, the widely cited safe limit is to remove no more than about a quarter of the root’s thickness, never more, and never on a large structural root near the trunk. Do not seal the shaved surface with tar, paint, or wound dressing — that traps moisture and actually speeds up rot. Wear eye and hearing protection and use both hands on the tool.
Important: shaving or cutting tree roots carries real risk to the tree and to you, and results depend entirely on the tree’s species, age, health, and your own technique. This article is general information, not professional arborist advice. If you choose to shave or cut any root, you do so entirely at your own risk and assume full responsibility for the outcome, including any damage to the tree, property, or yourself. When in doubt, consult a licensed, certified arborist before touching a root. Yardtally is not liable for any damage or injury resulting from these techniques.
What you’ll need for the job
For the mulch-bed approach that most homeowners should start with, you don’t need much. A few bags of shredded hardwood mulch are the core of it, and a landscape rake makes quick work of spreading and leveling the mulch evenly over the root zone. If you want to keep grass and weeds from pushing up through the bed, a layer of landscape fabric underneath the mulch cuts down on maintenance. And for the rare small root that genuinely needs cutting, a folding hand pruning saw gives you a clean, controlled cut — while the electric hand planer stays reserved for the advanced, at-your-own-risk shaving described above.
- “shredded hardwood mulch”
- “landscape rake”
- “landscape fabric“
- “folding hand pruning saw”
- “electric hand planer“
The bottom line
Exposed tree roots in your lawn are annoying, but the fix that feels most obvious — burying them under fresh dirt — is the one that quietly kills trees. The safe, arborist-backed move is to stop fighting the roots and mulch over them instead, keeping the mulch off the trunk. If you must smooth the ground, add only a light, loose layer and leave the root tops exposed to breathe, the way I did in my own yard.
Save cutting and shaving for small roots only, well away from the trunk, and when a root looks too big or too close to risk it, let a certified arborist make the call. Your trees took decades to grow. A weekend of doing this the right way keeps them standing for decades more.
Sources & further reading
Purdue Extension — What to Do With Tree Surface Roots: a Purdue urban forestry specialist lists cutting or grinding surface roots and adding heavy topsoil among the strategies that are NOT recommended, and points to 2–3 inches of wood mulch as the best solution.