Can Tree Roots Grow Upwards?

The short answer is yes, tree roots can grow upwards, though it is not their natural habit. Most tree roots grow horizontally near the soil surface, but when they encounter obstacles, poor soil conditions, or certain environmental triggers, they can turn and grow upward, sometimes breaking through the ground. Understanding why this happens and what to do about it can save your trees, your driveway, and your foundation.

What Causes Tree Roots to Grow Upwards?

Tree roots normally grow downward and outward in search of water, oxygen, and nutrients. When they grow upward, it is almost always a response to an environmental problem. The most common cause is poor soil structure. When soil becomes compacted, roots struggle to push through it. Instead of fighting the dense ground, they turn toward the surface where the soil is looser and more oxygen-rich.

Another major cause is lack of oxygen below ground. Roots need air to survive. In waterlogged or heavily clay soils, oxygen levels drop. Roots then grow upward to reach the air they need. This is especially common after heavy rain or in lawns that are overwatered.

Roots also grow upward when they hit a physical barrier. Sidewalks, foundations, underground pipes, and even large rocks can redirect roots. When the root can no longer go deeper or wider, it sometimes turns up. This is why you often see roots surfacing next to driveways and patios.

How Can You Tell if Tree Roots Are Growing Upwards?

The most obvious sign is visible roots above the soil line. If you notice roots lifting or breaking the surface, they are likely growing upward. Other signs include cracking pavement, raised sidewalk sections, pooling water near the tree base, and grass that dries out quickly around the tree because exposed roots steal moisture.

You may also see root suckers sprouting from exposed roots. These small shoots grow from the root itself and are a clear sign that the root is near the surface. If you mulch around the tree and the mulch stays dry or washes away quickly, that can also indicate upward-growing roots pushing the mulch aside.

Why Are Tree Roots Growing Above Ground?

Many homeowners worry that above-ground roots mean the tree is unhealthy or dangerous. In many cases, the tree is fine, but the roots are responding to a problem in the soil environment. Here are the most frequent reasons roots surface:

• Compacted soil: Foot traffic, lawn equipment, and construction compact the ground, forcing roots upward.
• Poor drainage: Roots surface to escape waterlogged conditions and find oxygen.
• Shallow soil: Trees planted in thin soil over bedrock or hardpan have nowhere to grow but sideways and upward.
• Competition: In a crowded landscape, roots from multiple trees compete for space and push each other to the surface.
• Improper planting: Trees planted too deep often develop girdling roots that eventually grow upward and wrap around the trunk.

Common mistake: Many people assume exposed roots are just a natural part of an aging tree. While some trees do develop surface roots as they mature, sudden exposure or swelling usually signals an underlying issue that needs attention.

Is It Dangerous When Tree Roots Grow Upwards?

It depends on where the roots are and how large they become. Surface roots themselves are rarely dangerous to the tree, but they can cause serious problems for structures. Roots that grow upward under sidewalks can lift and crack concrete, creating trip hazards. Roots that grow against foundations may cause cracking over time. In lawns, raised roots make mowing difficult and can damage mower blades.

For the tree, upward-growing roots can become problematic if they form girdling roots. These are roots that wrap around the trunk or other roots. As the tree grows, the girdling root tightens and cuts off the flow of water and nutrients. This can slowly kill the tree. Girdling roots often start underground but become visible when they grow upward and surface.

Best timing to check: Early spring and after heavy rain are good times to inspect for new root growth. The ground is softer, and new roots are easier to spot.

How to Fix or Prevent Upward-Growing Tree Roots

You cannot stop all upward root growth, but you can manage it. The key is to address the cause, not just the symptom. Start by improving soil conditions around the tree. Aerate compacted soil with a core aerator to allow roots to grow deeper. Avoid parking vehicles or placing heavy objects on the root zone. If drainage is poor, consider installing a French drain or redirecting downspouts away from the tree.

For roots that have already surfaced, never cut them without professional guidance. Cutting a large surface root can destabilize the tree and open the door to disease. Instead, follow these steps:

1. Apply a 2-3 inch layer of organic mulch over exposed roots. Use wood chips or shredded bark. Keep the mulch away from the trunk. This protects the roots, retains moisture, and encourages deeper root growth.
2. Add topsoil carefully over small exposed roots. Only add a thin layer, no more than 1-2 inches. Adding too much soil can smother the tree.
3. Install root barriers along sidewalks and foundations. These are rigid panels buried vertically in the ground that redirect roots downward.
4. Water deeply and less often to encourage deep root growth. Shallow, frequent watering trains roots to stay near the surface.

A useful tool for this job is a soil auger to check soil compaction before planting or mulching. You can find affordable options like the soil auger and planting drill bit set. For root barriers, look for heavy duty root barrier panels made from recycled polypropylene.

Can All Tree Species Grow Roots Upwards?

Nearly any tree can develop upward-growing roots under the right conditions, but some species are more prone to it. Silver maples, willows, poplars, and elms are known for aggressive, shallow root systems that often surface. These trees are natural surface-rooters, so upward growth is common.

Other species like oaks, pines, and spruces typically have deeper taproot systems and are less likely to push roots upward. However, even these trees can develop surface roots if planted in poor soil or too close to obstacles.

If you are planting a new tree in a tight urban space, choose a species with a less aggressive root system. Dogwoods, Japanese maples, and magnolias are better options for small spaces near sidewalks and foundations.

Common Mistakes Homeowners Make With Exposed Tree Roots

Many people try to fix surface roots in ways that actually harm the tree. Avoid these common errors:

• Cutting large roots flush with the soil: This can remove 20-50 percent of the tree's root system and cause the tree to lean or fall.
• Piling soil over exposed roots to hide them: This smothers the roots and can kill the tree within a few years.
• Pouring concrete or asphalt over roots: This traps heat and moisture, and roots will eventually crack the new surface.
• Using string trimmers on exposed roots: This damages the bark and invites pests and disease.

A better approach is to work with the roots. If a root is in the way of a walkway, consider rerouting the path or installing a root bridge rather than removing the root.

When Should You Call a Professional About Upward Roots?

Most surface roots are harmless and can be managed with mulch and good soil care. But call a certified arborist if you notice any of these signs:

• Large roots (over 2 inches in diameter) lifting a sidewalk or foundation
• Girdling roots visible at the base of the trunk
• The tree is leaning or showing signs of decline after roots have been damaged
• Roots are entering sewer lines or drainage pipes (this usually requires a plumber as well)
• The tree is large and close to the house, and roots are pushing against the foundation

An arborist can assess the tree's health, safely prune problematic roots, and recommend long-term solutions. For girdling roots, they may perform a root collar excavation using a tool like a root air excavation tool to remove soil without damaging the roots.

Does Root Type Matter for Upward Growth?

Yes, the type of root system a tree has influences how likely it is to grow upward. Trees generally have three root system types:

• Taproot system: One large root grows straight down with smaller side roots. These trees are less likely to develop upward roots. Examples: oaks, hickories, walnuts.
• Fibrous root system: Many thin, branching roots spread out near the surface. These trees are more prone to upward growth. Examples: maples, birches, cedars.
• Heart root system: A mix of deeper and shallow roots that spread outward. These trees can develop surface roots but are more balanced. Examples: pines, spruces, firs.

When choosing a tree for your yard, consider the root type. If your soil is compacted or you have limited space, a tree with a taproot system is a safer bet. If you already have a tree with a fibrous root system, plan for regular inspection and proactive mulching.

A helpful comparison:

What to Know About Tree Roots Growing Upwards

Upward-growing tree roots are a sign that something is off in the soil environment, but they are not always a crisis. The most important step is identifying the cause: compacted soil, poor drainage, shallow soil, or a physical barrier. Once you know why the roots are surfacing, you can take targeted action.

For most homeowners, the fix involves a combination of improving soil aeration, adjusting watering habits, and applying a proper layer of mulch. Avoid cutting or covering large roots. If the roots are near a structure, consider installing a root barrier or rerouting the obstruction. For girdling roots or large exposed roots near foundations, call a certified arborist.

Remember that a tree with surface roots is usually a healthy tree that is adapting to its environment. With the right care, you can keep both the tree and your landscape in good shape for years to come. If you need to manage soil compaction, a garden core aerator is a simple tool that makes a real difference without damaging roots. The bottom line is that tree roots can grow upward, but with observation and proactive care, you can direct that growth safely underground.

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