Most of a tree’s root system stays in the ground even after the trunk and stump are gone, and that is normal. Stump grinding chews up the stump and the thick roots near the surface within a few feet of it; everything deeper decays on its own over a few years. Full excavation of an entire root system is rare, expensive, and usually not worth it unless roots are actively lifting a slab, a sidewalk, or a sewer line.
If you are dealing with roots from a tree that is still alive and growing, the calculation is different. Cut the wrong roots and you can destabilize or kill a tree that otherwise had years left in it.
This guide covers both situations: what happens to roots after a removal, and how to think about roots on a tree that is still standing.
Root Removal vs. Stump Grinding: They Are Not the Same Job
“Root removal” gets used loosely, but there are really two different jobs:
- Stump grinding mills the stump down below grade, usually 4-6 inches, along with the visible flare roots right around it. This is the standard stump grinding service in Boise and it is what most homeowners actually want.
- Full root removal means digging out the entire lateral root system, sometimes with an excavator, so nothing is left underground at all. Roots on a mature tree can extend two to three times the width of the canopy, so this means tearing up a large section of yard, and it usually costs far more than the removal itself.
For the vast majority of yards, stump grinding is the right call. Full excavation only makes sense on a small lot before new construction, or when a root system is actively damaging something nearby. If you are still weighing the two options for a specific stump, our stump grinding vs. stump removal guide goes deeper on that decision.
| Stump grinding | Full root removal | |
|---|---|---|
| What comes out | Stump plus surface roots near it | Entire lateral root system |
| Typical yard | Any residential lot | Small lot, tight footprint |
| Common reason | Standard finish after removal | New construction, active root damage |
| Cost | Lower, added to a removal | Higher, priced separately on-site |
| Lawn impact | Minor, one dug area to fill | Larger area disturbed |
Boise’s compacted clay soil makes full excavation more work than in looser ground, since roots tend to spread wide and shallow rather than digging deep, which is one more reason grinding covers most situations here.
Not sure which one your yard actually needs? A free on-site estimate settles it fast: call (208) 247-9766 or reach out through our contact form and we will tell you straight whether grinding is enough or the roots need more.
What Happens to Roots Left in the Ground
Once a tree is cut down, its roots no longer have leaves feeding them sugar, so they stop growing and start breaking down. According to University of Illinois Extension, decomposition speed depends on stump size, species, and site conditions like sun and drainage; small roots can be gone in a couple of years, while large structural roots take longer. As they decay, they soften and lose structural strength, which is one reason old root channels can create soft or settling spots in a lawn.
Decaying roots are not dangerous the way a standing dead tree is. They will not fall on anything. The main practical issues are:
- Resprouting. Species that sucker, like cottonwood or certain maples and elms, can send up new shoots from roots that are still alive, sometimes several feet from the old stump.
- Fungus and mushrooms. Decaying roots feed wood-decay fungi, which is why mushrooms sometimes pop up in a ring around an old stump. This is a normal part of decomposition, not a sign that something new is dying.
- Uneven ground. As roots break down, the soil above them can settle slightly. It is worth backfilling and leveling low spots rather than assuming the yard will fix itself.
How to Kill Tree Roots So They Stop Sending Up Shoots
If a species is known for suckering, grinding the stump alone does not always stop new sprouts, because live root tissue can remain beyond the ground area. Penn State Extension describes the standard fix: treat the freshly cut, still-living wood right after cutting with a systemic herbicide labeled for stump and root use, focusing on the outer band of sapwood just inside the bark. Follow the product label exactly if you do it yourself, since the wrong product, timing, or dose can damage nearby plants, and anyone you pay to apply it needs a state pesticide applicator license. If shoots keep coming back season after season, it usually means live roots are still getting enough stored energy to push new growth, and the stump needs another treatment rather than repeated mowing.
Surface Roots on a Still-Living Tree
Surface roots that heave a lawn or trip people are a different problem, because the tree is still alive and depends on those roots. Cutting the wrong ones, or cutting too many at once, can starve or destabilize the tree. Penn State Extension frames the general rule of thumb this way: a root under about 2 inches across is usually safe to cut carefully, but anything larger has often become structurally important to the tree, and a certified arborist should weigh in before it comes out. Our guide to exposed tree roots covers what to do instead when cutting is not the answer, including covering roots with soil or mulch rather than slicing through them.
One rule matters more than any other: never cut large roots on the side of the tree a lean is toward. Those roots are doing the structural work of holding the tree up against gravity, and removing them can turn a leaning tree into a falling one.
When Roots Are Actually Damaging Something
Sometimes root removal is not about looks, it is about protecting a structure. A few situations come up often in Treasure Valley yards:
- Foundations. According to the Morton Arboretum, roots are rarely strong enough to crack solid concrete on their own; they are more likely to exploit a gap or crack that is already there, or to make a shallow foundation shift by pulling moisture out of the surrounding soil. Our foundation root damage guide walks through how to tell the difference between a root problem and a soil or drainage problem.
- Sidewalks and driveways. Surface roots from street trees are one of the most common calls we get, and the fix is not always removal. See our guide to roots lifting a Boise sidewalk for what the city expects and who is responsible for the repair.
- Sewer lines. Roots seek out moisture, and an aging clay sewer line with even a hairline joint gap can draw them in. This is usually a plumbing and root-cutting job, not a tree removal; our tree roots in a sewer line guide covers the warning signs and fixes.
In these cases, a partial root cut close to the structure, done carefully, often solves the problem without taking the whole tree down.
Can You Remove Tree Roots Yourself?
For a small, dead root you have already dug around, cutting it by hand with a root saw or loppers is reasonable homeowner work. Where it gets risky:
- Large roots on a living tree. As covered above, cutting a major structural root can destabilize the tree or trigger dieback you will not see for a season or two.
- Roots near a foundation, sewer line, or utility. Digging blind next to a footing or a buried line can turn a simple root cut into an expensive repair.
- Stump grinding itself. The grinder is a fast-spinning wheel of carbide teeth that throws debris; it is not a rental-store job most homeowners should tackle without the right protective gear and experience.
- Anything requiring herbicide. As noted above, stump-and-root herbicide has to be a product labeled for cut-stump use and applied exactly as the label says, and anyone you hire to apply it needs a state pesticide applicator license.
If the root in question is small, isolated, and not attached to a tree you want to keep, doing it yourself is fine. Anything bigger, or anything touching a structure, is worth a second opinion before you start digging.
Getting a Root Removal or Grinding Job Done Right
Because every yard is different, we do not price root work as its own line item. Root removal is quoted together with stump grinding, based on how many stumps, how large they are, how deep you need to go, and whether roots have grown into a sidewalk, a foundation footing, or utility lines. You can see typical grinding ranges on our tree removal cost calculator, then get a firm number with a free on-site estimate: call (208) 247-9766 or use our contact form and we will take a look before you commit to anything.
If a root is actively lifting a walkway or pressing on a foundation and you are worried about it getting worse before you can schedule a full job, say so when you call. We can prioritize a look at anything that seems to be getting worse fast.
Frequently Asked Questions
Do I need to remove tree roots after stump grinding?
Not usually. Grinding removes the stump and the roots right around it below grade, and everything deeper decays naturally over a few years. Full root excavation is only worth it if roots are actively damaging a foundation, sidewalk, or sewer line, or if you are clearing a lot for new construction.
How long does it take for tree roots to decompose?
It depends on the species, root size, and soil moisture. Smaller roots can break down within a year or two, while large structural roots can take several years. Roots decompose faster in moist soil than in Boise’s typically dry, compacted clay.
Will grinding a stump stop roots from sending up new shoots?
Sometimes not by itself, especially with species that sucker readily, like cottonwood. If shoots keep coming back, the freshly cut wood usually needs a labeled stump-and-root herbicide, applied per the label, rather than repeated mowing.
Can I just cut the roots that are lifting my sidewalk?
Sometimes, but not always safely. Cutting a large structural root close to the trunk can destabilize the tree, especially on the side it leans toward. A smaller, farther-out root is usually safer to cut than one right at the base.
Is it bad that mushrooms are growing where I removed a stump?
No. Mushrooms around an old stump are a normal sign that the leftover roots are decomposing, which is exactly what is supposed to happen. It does not mean a nearby healthy tree is at risk.
Do tree roots really damage house foundations?
Rarely on their own. Roots are much more likely to widen a crack or gap that already exists than to break solid concrete. If you are seeing new cracking near a mature tree, it is worth having both the soil and the tree looked at rather than assuming the tree is the cause.