While many of us appreciate certain plants for their visual appeal, fragrance, or culinary uses, it’s essential to consider the potential drawbacks they can bring to our gardens and yards. Specifically, some plants have invasive root systems that can cause significant damage and expense if left unchecked. The strength of these roots, particularly those found in certain trees, can be devastating if allowed to grow unchecked.
Often, the signs of damage aren’t immediately apparent, as the roots may not break the surface or cause noticeable harm until they’ve been quietly wreaking havoc underground for some time. As a result, it’s crucial to identify and avoid plants with destructive tendencies. Let’s take a closer look at some of the worst offenders.
What is an Invasive Root System?
When it comes to identifying invasive root systems, it’s essential to understand what sets them apart from others. It’s not just about self-seeding, as some plants can have impressive root networks without becoming invasive. The key characteristic of an invasive root system is its ability to extend beyond the plant’s immediate surroundings and cause damage to surrounding structures, such as foundations, swimming pools, fences, retaining walls, water pipes, and electrical lines.
This expansion enables the roots to interact with and compromise these elements, leading to significant consequences.
Warning Signs You Have Invasive Roots
As you explore your surroundings, you may notice subtle signs of an underlying issue. Vertical cracks in walls can indicate structural concerns, while buckling or raised areas in paths, concrete slabs, tiles, or cobblestones suggest settling or foundation problems. Similarly, clogged drains or unusual changes in water pressure could be a sign of hidden blockages or infrastructure issues.
Furthermore, ground disturbance or exposed roots around plants might be indicative of invasive root systems taking over the area. If you notice plants suddenly sprouting up everywhere, it may be a sign that one plant has gone rogue and is spreading its influence. And if you constantly remove these plants only to have them regrow with alarming speed, it’s likely that they’re highly resilient and adaptable.
In some cases, invasive roots can cause damage or disrupt the natural balance of an ecosystem. In other instances, a dominant plant may spread out, preventing other flora from growing nearby. This phenomenon highlights the importance of monitoring and addressing these issues before they escalate.
Plants That Have Invasive Root Systems
Yucca
Yucca, a plant within the Asparagaceae family, is renowned for its elegant, simplistic shape, which can adorn warm gardens with ease. However, it’s essential to plant yucca away from any structures as its robust roots have the ability to penetrate solid materials and cause damage. The plant’s root system consists of a long, sturdy taproot that delves deep into the soil in search of water sources. Complementing this is a network of fibrous roots that radiate outwardly, seeking moisture.
Unfortunately, these invasive roots can compromise water pipes, pools, and even concrete foundations. To mitigate potential issues, it’s crucial to plant yucca at a safe distance from structures and water pipes or confine the plant to pots. When using containers, care should be taken to ensure that the taproot doesn’t escape through the drainage hole and into the surrounding soil.
Ficus Tree
The Ficus tree (Ficus spp.) has long been a popular choice for landscaping due to its evergreen nature and ease of growth. Its attractive appearance is also a major draw. However, the Ficus tree’s root system is remarkably invasive, posing a significant risk to nearby infrastructure such as paths, driveways, buildings, or underground utilities if not properly contained.
This issue can be mitigated by planting the tree at a sufficient distance from any potential damage points or investing in a root barrier installation when the roots mature. For those who are passionate about Ficus trees, shaping them into rounded balls and placing them in containers near entryways can create a striking visual effect.
Jacaranda Tree
The Jacaranda tree (Jacaranda spp.) boasts an impressive root system, with its upper sections occupying approximately 25 inches of soil. In fact, this extensive network can spread outwards, extending to a width equivalent to twice the size of the tree’s canopy above ground.
While these trees are undoubtedly stunning, it’s essential to carefully consider where you plant one, as they have the potential to grow quite massive, with their underground root system mirroring their above-ground size – in fact, reaching an astonishing 50 inches wide or more.
Gum Tree (Eucalyptus)
You may be well-acquainted with this iconic Australian species (Eucalyptus spp.) if you’ve spent time in California. One of its most notable features is its substantial and far-reaching root system. The primary taproot can delve as deep as six feet, while the remaining 90% of the roots are concentrated within the top 12 inches of soil. To ensure stability, the tree spreads these shallow roots incredibly wide, radiating up to 100 feet away from the trunk.
This sprawling network poses potential risks if planted near buildings, infrastructure, or other vegetation.
Magnolia
While not as notorious for causing problems as some tree species, magnolias (Magnolia spp.) can still become an issue if planted too close to structures like houses, sheds, or barns. In fact, these trees typically need to reach a height of around 15 feet before their root systems start causing trouble. However, one major concern is the sheer density and spread of their shallow roots, which can stifle the growth of surrounding plants.
To avoid potential issues, it’s recommended to plant magnolias at least five feet away from pathways and at least 30 feet from buildings.
Silver Maple
While some maples, such as sugar maple (A. saccharum) and red maple (A. rubrum), are not notorious for invasive root systems, silver maple (A. saccharinum) is a different story altogether. Its spreading roots have been known to cause significant damage to foundations and any underground structures that get in their way. As such, it’s crucial to plant silver maple at least 100 feet away from your house, barn, or outbuildings to prevent potential issues.
Sycamore
While some trees on this list boast extensive root systems that delve deep into the earth, the sycamore maple (Acer pseudoplatanus) takes a different approach. Instead of developing deep roots, it spreads its roots wide, often causing issues with nearby paths and structures. The roots typically remain within the first six feet of soil, but can extend beyond the dripline, posing problems if planted in an unsuitable location.
To mitigate these concerns, it’s essential to plant sycamore maples at least 12 feet away from walkways or driveways, and a minimum of 25 feet from any buildings.
Mulberry
While many people choose to plant mulberry trees (Morus spp.) due to their rapid growth rate, it’s essential to consider the potential impact on surrounding infrastructure. For instance, if a mulberry tree is located near a water pipe with even the slightest leak, its roots will actively seek out and compromise the integrity of the pipe.
Furthermore, although mulberry tree roots won’t directly damage building foundations, they can still cause stability issues by weakening the soil around those foundations, leading to potential problems.
American Elm
The American Elm (Ulmus spp.) is characterized by a relatively shallow root system, which can sometimes lead to invasive roots. While it’s not always problematic, certain circumstances can trigger this issue. For instance, mature and larger trees have been known to seek out moisture in sewer pipes, causing potential damage.
As such, it’s crucial to plant the tree away from driveways and paths, as these will likely suffer if they’re situated between the tree and a water source, such as pipes or a water tank on your homestead.
Poplar
Poplars, belonging to the Populus spp., are renowned for their rapid growth rate, making them a sought-after option for landscaping. These trees can reach astonishing heights of up to 150 feet, accompanied by expansive canopies that provide ample shade. Moreover, their roots can extend an impressive distance, often reaching two or even three times the height of the tree itself.
Notably, these roots can exert significant influence on building foundations, but they tend to gravitate towards moisture sources like water and sewer pipes rather than structural components.
Mint
While discussing towering trees that reach 150 feet tall, you might wonder how we’ll get to mint. The connection lies in its invasive nature. Mint (Mentha spp.) has underground roots that spread rapidly and sprout new growth anywhere. Once planted, it’s often a permanent fixture. While it won’t damage buildings or pipes, it can still outcompete other plants for space and resources.
To prevent this from happening, consider planting mint in pots that can be placed on the surface of your garden or in containers buried beneath to contain its spread.
Bamboo
Bamboo (Bambusoideae subfamily) has garnered widespread popularity among gardeners for its versatility in landscaping. While it’s possible to keep it under control through the strategic use of root barriers and selecting varieties that don’t have an extensive root system, some types can still wreak havoc.
Clumping bamboo tends to remain compact and well-behaved, whereas running types can cause significant damage with their rhizomes extending up to 30 feet from the plant, compromising foundations, paths, patios, and drains. To mitigate this issue, consider planting it in large containers equipped with root barriers specifically designed for bamboo roots.
Bellflower
The Bellflower (Campanula spp.), with its dainty appearance, is a force to be reckoned with when it comes to spreading its roots. Its ability to push through even the most unexpected places, like asphalt, is a testament to its resilience. But don’t let that surprise you – its underground rhizomes can spread quickly, making it a great candidate for container planting, where its enthusiasm can be better contained.
Obedient Plant
The obedient plant (Physostegia virginiana) is a misnomer, as its name suggests. In reality, this invasive species can spread rapidly through fibrous roots and rhizomes, making it notoriously difficult to eradicate once established. It’s not uncommon for the plant to reappear in unexpected areas of your garden long after you thought you had removed every last bit. This behavior is reminiscent of other plants that are notorious for their aggressive propagation methods.
To mitigate this issue, consider planting the obedient plant in containers, rather than allowing it to spread unchecked through your garden.
Bee Balm
Bee balm (Monarda spp.) has gained widespread popularity in gardens globally, but its invasive nature can be a concern. Its extensive root system is capable of spreading far and wide, often producing new shoots in unexpected areas. This trait is reminiscent of its mint family relatives, where underground stolons enable them to quickly colonize surrounding soil. Bee balm typically grows in dense clumps, which can be deceiving as new plants emerge, only to soon spread outwards via rhizomes.
Eventually, the mother plant will succumb, leaving behind a plethora of new individuals that may not have been intentionally planted.
Using Plants with Invasive Roots
When considering adding these plants to your landscape, don’t be deterred by their potential to spread. Instead, take a thoughtful approach to placement, keeping in mind factors like root growth and rhizome expansion.
For larger properties, it’s essential to plant away from buildings and underground infrastructure to avoid any potential issues. In smaller areas, pay close attention to the mature size of the plants and how their roots may impact surrounding growth.
