A Focus on Foundation Planting

Despite the fact that many homeowners want foundation planting, few people understand what its true role is. This misunderstanding leads to some widespread foundation planting mistakes that a wise landscape designer will avoid. 

What is Foundation Planting?

Foundation planting refers to the plants you grow around your house, or, more accurately, around your house’s foundation. 

In most cases, a small portion of a home’s foundation will be visible from the exterior. Foundation planting replaces this small portion of the foundation with something of greater ornamental value, often a shrub, perennial, or annual plant. 

One Major Foundation Planting Mistake

The biggest mistake people make when creating foundation plantings is choosing plants that are simply too large. The reason this happens is that many fail to anticipate the mature size of a plant before planting it. 

Although many plants look quite small when they first go into the ground, some will quickly expand wider than their growing space allows. In foundation planting, this means the plant may begin to engulf your home, going far beyond its original purpose of blocking a few inches of exposed foundation. 

The prevalent phrase “right plant, right place” is an adage you should follow when creating any type of planting, but it’s especially true regarding foundation planting plans.

How Large Plants Present Problems for Foundations

Allowing a tree or shrub to grow into the exterior of a house is undesirable from an ornamental perspective. Still, what’s more concerning is what can happen underground. 

Although this can vary by species, root systems often spread across larger distances than the above-ground portions of the plant. When a vigorous root system is too close to a house, little prevents it from growing into the foundation. These roots can damage the foundation by forming cracks that allow water to seep inside and weaken the foundation’s strength. 

This is especially a problem for any foundation that includes mortar, such as brick or cinderblock foundations, as the presence of mortar makes it easier for roots to work their way into the wall. That said, even if your foundation does not include mortar, certain roots can still create cracks in the foundation wall, although it will likely take longer than if mortar were present. 

By no means do roots account for the majority of foundation problems. Additionally, growing a large plant near your foundation does not guarantee its roots will cause foundation issues. Instead, it just makes that outcome more likely than it needs to be. 

Creating Foundation Planting Plans the Right Way

The best way to avoid the problem outlined above is to never plant large shrubs and trees in close proximity to your foundation. 

What’s even more effective is actively choosing plant species that you know will grow well in your area and have a root system that’s unlikely to interfere with the structural integrity of your home. 

Of course, regardless of your project, you should select plants that grow well in your region, are non-invasive, and are suited to the sun, water, and soil conditions in your intended growing location. 

After fulfilling those requirements, you’ll want to consider two main factors. 

Evaluating Root Systems for Foundation Planting Plans

This may seem complex, but you don’t need to have any special knowledge to evaluate a plant’s root system. Instead, a quick search online will reveal what you need to know.  

Specifically, research whether the plant species you want to grow has an “aggressive” or “invasive” root system. Both terms essentially mean that the roots are known to spread and may cause problems for underground structures, such as your foundation. 

As a quick note, if a plant has an invasive root system, that does not necessarily mean that the species itself is invasive to that area. For example, Acer saccharinum, or silver maple, is native to the eastern part of the US, meaning it is not an invasive species there. Still, this plant does have an “invasive” root system, meaning it spreads aggressively regardless of where it grows. 

Spacing Guidelines for Foundation Plantings

Another essential element of foundation planting is spacing. This is where the mature size of a plant is important. Again, it’s easy to find the mature size of a plant online, and, in many cases, when you purchase a plant, it will come with a tag that indicates how large it will grow. 

The listed size of a plant’s mature width, or spread, typically represents the diameter of the plant at maturity. For planting, you’ll want to focus on the radius dimension by dividing the diameter in two. Let’s use another example to illustrate this point. 

Syringa vulgaris, also known as lilac, can have a 12-foot spread at maturity. Dividing that number in half gives you a six-foot radius. This means that from the center of a lilac shrub, it’s safe to assume the plant could expand six feet in any direction. As such, it’s best not to plant this species within six feet of your foundation. 

Proper spacing is most important for large shrubs and trees, especially when they are known to have aggressive root systems. On the other hand, perennial plants and annuals rarely have expansive root systems that can damage your foundation. The same can be true for many shrubs, including small and dwarf varieties. 

What’s the Value of Foundation Planting?

When planning foundation plantings, it’s crucial to avoid some common pitfalls. After that, it’s time to focus on how a foundation planting can dramatically enhance the beauty of your home. 

Foundation planting can be attractive in its own right, but it can also add considerably to the curb appeal of your home. Likewise, a landscape design is not fully complete without considering how foundation planting can complement your house and the design as a whole. 

Want to Do Foundation Planting the Right Way?

I’m a landscape designer serving property owners in Western Massachusetts and Northern Connecticut. If you’re interested in foundation plantings or any other type of landscape design project, I encourage you to contact me at any time.