Laurels are among the most popular evergreen shrubs often used for hedges. Some varieties even have beautiful blooms that can enhance the appearance of your garden during the blooming period. However, it is best to understand the potential risks these beautiful shrubs pose to essential structures in your area.
Laurel roots can cause damage to structures, such as pipes and underground wiring or cables. Different varieties of laurel shrubs have various root systems ranging from shallow and horizontally invasive to deep taproots. Either way, they can damage nearby structures.
Laurel is a fast-growing, broad-leafed plant that makes excellent privacy screens and hedges, but their strong growing tendencies can cause issues with structures and plants nearby. Further in the article, we will discuss what structures laurel roots can cause damage to and how you can avoid such problems. Read on!
Structures That Laurel Roots Can Damage
Laurels are rapidly growing evergreen shrubs, making them ideal plants for hedges. Their rapid growth is often thanks to their root systems that efficiently collect moisture and nutrients from the ground.
As discussed, various laurel plants have different root types. The English laurel (Prunus laurocerasus), for instance, has competitive roots that tend to spread aggressively for better chances of gaining access to soil nutrients.
While it is beneficial for the plants, some gardeners may find it troublesome, as this trait makes laurel roots a potential threat to structures it comes across. Let’s take a look at how they can affect certain structures:
Laurel plants typically have woody roots that either aggressively spread horizontally or burrow deep into the ground. Both mechanisms enable laurel roots to damage underground pipes they come across.
Stainless pipes are generally safe because they will be too sturdy for the roots to penetrate. Plastic pipes, on the other hand, may be at a higher risk of damage.
However, it is also important to note that some roots tend to grow away from a barrier, provided laurel roots consider the pipes a barrier and avoid going through it.
Even so, laurel roots may branch out in other directions and twist around the pipes. As the roots get bigger and stronger, they might squeeze around the pipe. The pipe may break or burst depending on how much force the roots exert.
Underground Wires or Cables
Since several laurel varieties have invasive roots, they will likely overlap or intertwine with underground cables or wires. Depending on the direction of growth and movement of the roots, they can cause significant damage to these soft structures.
Sometimes, pipes protect underground wiring. As mentioned above, laurel roots may cause the pipes to burst or break.
Laurel roots can damage other plants by strangling their roots. Many laurel varieties have laterally growing woody roots that can entangle with the roots of their neighbor plants. If the neighboring plants have weaker roots, the sturdier laurel roots may easily damage them.
Moreover, the competitive nature and better salt tolerance of laurel roots can dehydrate nearby plants as they compete for moisture from the soil.
Rainy days in coastal areas or fertilization seasons typically introduce more salt into the soil. Other plants may have a slower moisture absorption capacity during this time due to the increased salt concentration in the ground.
Many salt-tolerant laurel shrubs can take advantage of this situation by absorbing most of the available moisture in the soil, leaving the other plants dehydrated.
Some potted laurel varieties can quickly outgrow their pots, requiring regular repotting to accommodate their growth. Typically, the roots will stop spreading once they hit the pots.
However, this can significantly reduce the quality of the plant. The leaves may start to wilt, or the plant will suffer from stunted growth.
As the plant gets bigger, the roots may try to spread in every direction possible until the pot bursts. To prevent that, you must prune the roots before moving the plant to a bigger pot.
Some laurel varieties can damage the lower part of wooden walls buried underground. That is why keeping laurel hedges away from your house is best.
When planted directly into the ground, these plants’ roots tend to explore freely and invasively, putting nearby structures at risk of damage. Their sharp and woody roots may pierce through walls and destroy them.
Although these problems don’t happen instantly, leaving your laurel plant’s roots unattended for several years can cause irreparable damage to vital structures.
Root Characteristics of Some Common Laurel Varieties
Laurel shrubs are generally evergreen shrubs with dense leaves. However, there can be subtle differences in the root characteristics of different varieties.
Here are the root characteristics of some common laurel varieties and cultivars:
English Laurel or Cherry Laurel
Scientifically known as Prunus laurocerasus, the English laurel can reach up to 20 feet (6 m) tall and 10 feet (3 m) wide. This size demands sturdy roots that can physically support the massive spread of the plant and provide sufficient moisture and nutrients.
Because of this, the English laurel’s roots have evolved to be competitive. Often, their roots will also compete for moisture with neighboring plants. If you want a hedge composed of English laurels planted side by side, you must space them appropriately to prevent the roots from overlapping and intertwining.
Carolina Cherry Laurel
The Prunus caroliniana is a close relative of the English laurel. Its shallow roots can spread outwards and produce suckers, increasing the spread of the plant. It also self-seeds, increasing the risk of damage to structures if you don’t keep the new growths under control.
Mountain laurel (Kalmia latifolia), also known as Calico bush or mountain ivy, is one of the few laurel varieties with poisonous roots. Other varieties contain toxic chemicals only in the bark, stem, or leaves.
They usually have a deep taproot system to help them stay in place, as they typically grow in mountains or slopes. The taproot system also allows the plant to collect moisture from deep under the soil’s surface to adapt to its dry habitat in the wild.
Some lateral roots also spread out from the central taproot for additional physical support and moisture acquisition.
Bay Laurel or Sweet Bay
Bay laurel (Laurus nobilis), also known as sweet bay, is a laurel often grown in pots. However, it can grow so tall into a tree, requiring regular pruning of the roots.
The roots of bay laurel are shallow but can spread when planted in the ground. They are pretty invasive and can damage sensitive underground structures.
Inside pots, you will need to prune the roots and move the plant to a bigger pot to accommodate the plant’s growth. Fully matured pot plants will require regular pruning of the branches and roots.
Portugal laurel (Prunus lusitanica) has the same genus as the English laurel. However, it grows relatively more slowly and is more drought-tolerant. These traits make their roots less competitive than the English laurel’s roots.
Nonetheless, the roots of Portugal laurel may still spread aggressively in nutrient-poor soil or if there are plenty of competitors nearby.
How To Prevent Laurel Roots From Damaging Structures
The first thing to do if you want to prevent laurel roots from damaging important structures is to understand the growth characteristics of the laurel variety you are getting. That way, you can estimate its growth speed and maximum spread.
Since many laurel varieties tend to have invasive roots, the best way to prevent them from damaging structures is to keep them at a safe distance. If you plan to grow them in your home garden, keep them at a distance of at least half the size of their spread at full maturity.
For instance, if you expect an English laurel shrub to spread 10 feet (3 m) at maturity, its roots are likely to spread almost half as wide. Therefore, keeping the shrub roughly 5 feet (1.5 m) away from your house should be safe.
Another thing to consider is the location of pipes or underground wirings. Be sure to consider that when planning where to grow your laurel shrubs. As much as possible, keep the shrubs away from such structures.
If you want to grow laurel shrubs for a hedge, you may want to keep them at least 3 feet (90 cm) away from the next plant. It will help prevent the roots from overlapping and strangling one another. It can also provide the plant with enough space to search for moisture and nutrients from the soil.
If you have the potted varieties, you should ensure that you prune the roots once a year to prevent them from creating cracks or breaking your pots.
Laurel roots are typically woody and can be laterally or vertically invasive. These traits result from their adaptation to improve their chances of survival. As a result, they can unwittingly cause damage to nearby structures.
Keep your laurel plants at a safe distance to prevent their roots from damaging important underground structures.