3 Major Problems With Tree Roots in Gardens

Problems caused by tree roots can be found in every neighborhood in northern Virginia – although, in many cases, those problems are preventable with a little forethought and regular maintenance.

Problems with tree roots fall into two main categories. Either the roots themselves have a problem such as girdling, rotting, lack of moisture, or a pest or disease that leads to the decline of the tree, or the roots cause problems in their surroundings.

If you have some basic knowledge of trees, or if you love planting trees in your garden, you must have heard about the issues tree roots can cause. Tree roots might appear harmless and nature supportive, but their invasive growth can be irritating and expensive to remove as you may have to spend money on arborist services.

Tree roots can be problematic in many ways, such as:

• Affecting the foundation of the building
• Affecting sidewalks and driveways
• Disturbing the sewer system
• Getting in your way

Being buried underground, roots are the parts of your trees that probably receive the least direct attention. However, a healthy root system is vital to support your trees both physically and nutritionally.

Knowing how to spot root issues in the trees in your yard can save you from an unexpected disaster that could happen if one of your trees fell on your home. Here are two common tree root problems you should know.

1. Lawn Overgrowth

Trees in your lawn may look nice, but they can often experience problems due to the conditions of the soil or turf. Tree roots will naturally expand until the diameter of the root system is approximately the same as the drip line or the edge of the tree canopy where water drips to the ground.

In a lawn or yard, trees are often confined to spaces smaller than they would naturally develop into. Furthermore, tree roots in irrigated lawns tend to stick very close to the surface where water is abundant. These factors can cause roots to overgrow and emerge from the surface, where they create tripping hazards and unwanted obstacles for your lawnmower.

Mulching in a wide circle around the base of your trees will help to contain overgrowth by reducing the amount of moisture on the soil’s surface. If possible, keep sprinklers and other irrigation systems away from your trees and focused on other areas of your yard.

Girdling occurs when tree roots grow around and constrict the trunk of a tree. Girdling creates a tourniquet effect that cuts off important water capillaries inside the tree. Severe girdling can kill trees by constricting their circulation completely.

Girdling can occur when the roots of a tree are constricted in very early development. Most often, a girdled tree has been left in the planter for too long or was planted in a hole that was too narrow. You should also break off any roots that appear to be encircling the main stem before planting to minimize the risk of girdling.

Trees naturally begin to flare outward near the base of the trunk where the roots branch away. Trees with girdling roots may have no apparent root flare, with trunks that are the same size or even narrower at the base. If you notice this symptom in your trees, consult an arborist to make a plan to remove the girdling roots without damaging the main stem of the tree.

The health of your trees is always dependent on the health of their roots. Watch out for these common tree root problems so you can be a better caretaker for your trees! 

Wrapping Up …

Roots are a vital part of a tree and should be protected whenever possible. By planning ahead, planting trees in the right place, proactively managing root growth and regularly inspecting foundations and sewer lines, you’ll give your trees the best chance of growing into healthy, beautiful specimens that enhance the value of your property.

If the Tree Just Has to Go

Sometimes, roots just create too many problems and the tree has to be removed. However, cutting down the tree may not be enough; roots can continue growing after tree removal and the stump can sprout new growth. You’ll need to get rid of the entire tree stump by grinding it out if you want to permanently solve the problem.

Tree Roots Affecting Your Sewer System

Have you ever come across broken and cracked sewer pipes? Do you think that’s because of the invasive root growth? Well, that’s not true. Your sewer pipes are not broken by the roots. Roots only have a little resistance, and they grow wherever they find space. Sewer pipes usually break due to the shifting of soil, and that can be due to the invasive growth of roots in the soil.

Another way to remove roots from pipes is by using foam-based chemicals. Therefore, it is better to plant trees away from the sewerage system. Plus, it is better to learn about the particular plant and its growth rate prior to planting.

Tree Root Problem #3 – Cracked & Lifted Sidewalks, Driveways, and Patios

As a tree grows and the root system expands, it can lift nearby concrete sidewalk slabs, crack paved areas, and overturn pavers or flagstone surfaces. Usually, this happens because the tree was planted where it shouldn’t have been. So what can you do about it?

If the tree is still young, you may be able to move the tree to a better location.

If the problem is caused by a mature tree that can’t be moved, you have four options:

• move the sidewalk/driveway/patio,
• make more space for the roots,
• remove some of the roots (we don’t recommend this) or
• remove the tree.

Moving the concrete or paved area away from the tree is a better choice than simply repairing is; repairs won’t last long if the underlying problem isn’t addressed. For example, reroute a sidewalk further away from the tree (you’ve probably seen those meandering sidewalks before) to give the roots more room to grow, or create a bridge over the roots. You’ll see the bridge option often in state parks.

Other options include using an air spade to remove some of the soil below the roots (particularly if it’s highly compacted) to create more room for them. The sidewalk will need to be replaced in this instance, and a meandering version still might make the most sense.

Some choose to prune away offending roots, but this should be attempted with caution, as roots help a tree remain stable. In many cases, roots will grow back within a few years anyway. Cutting too many roots or the wrong ones can kill the tree, so root pruning should only be attempted by a tree care professional.

Never pave over the roots of a tree, as doing so will almost certainly kill the tree and lead to many problems in the future. If you have to put in a driveway, consider bending it away from the tree (similar to the meandering sidewalks), or using pavers. The pavers are less likely to crack and easier to replace.

What’s the problem with tree roots?

Roots are how a tree gets much of the water, oxygen, and nutrients necessary for its survival. The farther the roots spread, the better able to tree is to get the resources it needs.

A wide network of vigorous roots also helps to anchor the tree so it’s less likely to fall during high winds or a storm.

While these issues are problematic, frustrating, and oftentimes very expensive to fix, they are not necessarily the tree’s fault.

Don’t believe us? Keep reading.

Tree root issue #4 – Roots are a Tripping Hazard

Exposed roots usually happen from soil erosion or from frost heaving, where the soil repeatedly freezes and thaws, contracting and expanding with each freeze/thaw cycle and pushing roots toward the surface.

Exposed roots should NOT be cut or covered with soil. Cutting the roots can stress or kill the tree, and covering them with a thick layer of soil can cut off the oxygen supply.

With exposed roots, mulch is usually the best option. Cover the roots with one or two inches of compost or wood chips (more is not better!), ensuring that the mulch doesn’t touch the tree’s trunk. Avoid “mulch volcanoes” at all costs.

Mulch helps retain moisture, keeps the ground from eroding further, and acts as an insulator, protecting against further frost heaving.

Common Problems Caused by Tree Roots

To understand the impact that tree roots can have, it is important to keep in mind that the roots of a tree spread two to three times as wide as the radius of the canopy. In dry conditions, they can spread even as much as five times as wide. For example, a tree with a canopy of 12 feet—which equals a radius of six feet—the roots can spread 18 to 30 feet from the trunk.

Also, most roots are nearest to what they need to survive—water, oxygen, and nutrients—and that is naturally near the surface. That’s why most tree roots are located in the upper 18 to 24 inches of the soil. 

Damage to Underground Pipes

To prevent this from happening, practice sewer-safe landscaping:

• Know where the pipes are located on your property and avoid planting anywhere near them. Plant trees as far away from the pipes as possible.
• Choose trees that to cause fewer problems, such as amur maples, Japanese maples, flowering dogwoods, or crabapples.

Damage to Pavement and Sidewalks

Tree roots can grow close to and underneath pavements and sidewalks. If the roots are near the surface, they can lift the pavement, which not only causes damage but also creates a tripping hazard. When that happens, the choice is often between saving the tree by moving the pavement farther away from the tree roots or severing the encroaching roots of the tree and taking the risk of killing the tree to save the pavement or walkway. 

Ways to prevent this include:

• Plant smaller trees and keep a minimum distance of four feet between the tree and the pavement. A rule of thumb is to plant trees with a mature height of less than 30 feet at least five feet away from the sidewalk, and trees with a mature height of 50 feet not closer than five to six feet from a pavement. Stay away from any trees that exceed that size.
• Install mechanical barriers along the tree-side of the pavement to prevent roots from growing underneath. The barriers, which can be made of plastic or geotextile fabric, force the roots to grow deep in the soil, so they won’t be able to lift the pavement. Place the barrier one foot deep in the soil and draw an imaginary line from the tree trunk to the sidewalk, then place the barrier five to six feet along the sidewalk in either direction.

Surface Roots as Hazards

If you have a maple tree growing in your backyard, its big, strong roots protruding from the surface might be a familiar sight. This often occurs on a slope where soil erosion leads to root exposure. And after a winter with warm spells, it can get worse, as the freezing and thawing cycle causes frost-heaving.

Not only are these surface roots unsightly, they are also hazardous. And they can be a real headache when you are mowing the lawn. Because they are so exposed, the roots are also prone to injury.

Instead of severing the roots, mulch the area under the tree with hardwood mulch or well-matured loose compost. Note that you should not cover the roots with more soil. Adding more soil starve the tree of water, air, and nutrients. Raising the ground level by adding soil is almost never advisable.

Mulching has several benefits. Mulch lets plenty of oxygen through and at the same time insulates the soil, so it reduces the effect of frost-heaving. Replacing the grass with mulch makes mowing unnecessary and the tree and the lawn won’t compete for water and nutrients any longer.

Tree Root Problem # 1 – Roots in Your Sewer System (or Other Pipes)

Root growth is opportunistic – tree roots tend to take the path of least resistance. When it comes to pipes, roots can only go where there is already an opening – they can’t “break into” a pipe. But if there’s a leak in the pipe, roots will quickly find the source and grow into it.

If there are roots in your sewer system, it’s usually due to a cracked joint in the pipe. Cracks and leaks are typically caused by shifting and movement in the surrounding soil as it shrinks and expands in response to moisture levels.

Once roots enter a sewer system or other water-carrying pipes, they are very difficult to remove. You’ll need to have the roots mechanically cleared from the pipes at least every year (an expensive process). Alternatively, there are chemical foam treatments that can be used to kill roots within the sewer pipes.

However, the only permanent solution is to replace the pipes to eliminate any cracks or gaps through which roots can enter.

Invasive Tree Roots And The Foundation Of Your Home

The largely growing tree roots can invade inside the cracks and can damage the foundation of your building. If you have an old built house or if your house’s foundation is weak, you must be very careful regarding your plant choices.

It is better to grow a tree not too close to the foundation of your house. And if you have small planting space, then only plant those trees with a slow growth rate. Well, that’s because a tree normally grows the same amount inside the soil as the outside. And the rapidly growing roots can shift the soil causing cracks in the foundation.

Furthermore, you’re supposed to water the plants regularly and properly. If roots do not find enough water for the tree, they will penetrate deeper and farther, causing damaging the foundation.

Tree Roots Affecting Sidewalks And Driveways

The proper planting of a tree plays a major role in its roots’ growth. For instance, if you plant an invasively growing tree too close to the surface, the roots can invade with the landscape elements, resulting in damage and cracking of sidewalks and driveways. This problem most commonly occurs in compact soil where the roots have to grow close to the surface.

The final solution to this issue is the removal of the tree to avoid your property damage. But, if you want to grow trees in that particular area, it is better to prune the roots on time with a professional arborist’s help.

Tree Roots Getting In Your Way

If the roots are getting in your way, causing you to trip and damaging your property, it is better to cut down the tree. There’s no other way. But, if you want to keep the tree instead of the fact that its roots are taking a part of your driveway, there’s only a single safe solution to do so. And that is by a mulch.

Do Tree Roots Damage Foundations?

Not necessarily. Trees that are planted too close to a foundation can lead to multiple problems, but not always because of the roots. The soil around a foundation is usually very dry, especially if the area is covered by a roof overhang. Meanwhile, tree roots grow towards moisture, so they will usually expand in the opposite direction away from the foundation. 

If there are cracks in the foundation that were caused by other circumstances, such as soil pressure or shrinking, smaller tree roots might penetrate those cracks, but they usually won’t create more structural damage than what’s already there.

Any problems caused by tree roots should not deter you from planting trees even if your yard is small.

Tree Root Problem #2 – Tree Roots in Building Foundations

If there is tree root damage to your foundation, one of two things (or possibly both) is true:

• the tree was planted too close to the building, and/or
• there was a recent drought in the area.

Plant the Right Trees in the Right Places

We can’t stress enough the importance of planting the right tree in the right place.

Did you know that most trees have as much mass below ground as they do above it? Or that the majority of that is concentrated in the top 18 to 24 inches of soil? Tree roots can spread anywhere from 2 to 6 times as far as the tree’s canopy, depending on surrounding conditions and tree species.

The best advice is to plant trees well away from your house (or any other building), as well as paved areas (like sidewalks and driveways) and sewer and water lines. A minimum of 10 feet is suggested for all trees, while those with spreading or water-hungry roots are better placed 25+ feet away. And trees with vigorous, invasive roots systems, such as willows, American elm, and silver maple, are best kept even farther away.

Trees need plenty of space to grow (both above and below ground) but some are more petite than others. If you have limited space, check out our article on best trees for small spaces.

Keep Trees Well-Watered

Drought conditions can cause foundations to shift due to the lack of moisture in the soil. And because trees also remove moisture from the soil in an attempt to survive, they may indirectly add to foundation problems.

Roots exist, in part, to bring moisture and nutrients to the tree. If there isn’t enough moisture in the soil surrounding the tree (such as during a drought), roots will grow toward any nearby sources of water. That includes foundation plantings, such as flowers and shrubs, that receive regular water from an irrigation system. As with sewer and water pipes, tree roots will infiltrate cracked foundations in search of moisture. So while you may find roots growing into, or even through, your home’s foundation, the roots aren’t the cause of the cracks or leaks.

To prevent roots from entering your home, be sure that your trees are adequately watered so they don’t have to seek out water elsewhere.