Spacing Foundation Plants Correctly

Many people plant shrubs too close to their houses and too close to one another. It’s an easy mistake I’ve made myself. Give your foundation plantings room to breathe!

Here are five time-tested tips for correctly spacing your foundation plantings:

  1. Maintaining a two-foot “no plant” zone between your foundation and your plants.
  2. Creating a generous planting bed beyond the two-foot “no plant” zone.
  3. Choosing foundation plants that won’t outgrow the space.
  4. Siting your plants based on their dimensions at full maturity.
  5. Adding mulch and groundcovers to fill in open spaces between larger plants.

Maintaining a minimum two-foot “no plant” zone between your foundation and your plants

Usually, a home’s roof overhang extends about 2′ beyond the perimeter of the house, blocking the area below from rainwater. Therefore, anything you plant in this space might not thrive.

Rainwater does not reach the planting area below your roof’s overhang.

You don’t want to the added maintenance of having to baby plants that aren’t receiving rain. And you normally want to keep excess water away from your home’s foundation.

This prevents water damage to your foundation and a damp basement (consult with a foundation professional about your specific soils. In some cases, soil that is too dry can also be a problem).

Ideally, this no-plant zone is best filled with gravel, which helps to wick away moisture from the foundation. It’s often called a “gravel drip edge” (not to be confused with a roof element also called a drip edge).

The gravel can be very basic or decorative, depending on your taste and budget. Shredded bark mulch or low ground cover could also be good options here.

Having this space behind your foundation plantings also makes it easier for repainting, window-washing, and repairs.

Foundation plants should not touch your home’s exterior.

Vegetation that touches your house can damage wood, paint and masonry, and it creates shelter for pests. Plant roots can be a major problem for underground pipes and more.

Too-tight planting decreases air circulation around the plants, which promotes the growth of mildew and harbors moisture-loving insects.

Snow, ice, and rain coming off the roof can destroy foundation plants.

You’ve also got to think about potential plant damage from ice and snow sliding off of the roof, if that’s a problem in your area.

I have suffered personal heartache from watching my otherwise blissful boxwood become flattened by an avalanche of roof snow!

Make sure your no-plant zone is deep enough to accommodate any unpleasant winter phenomena. 

The same holds true for heavy rain runoff. If you see a line gouged into the ground by storm water coming off your roof, don’t plant there! Your plants will sustain damage from heavy rains if you do.

Creating a generous planting bed beyond the two-foot “no plant” zone

Think of your foundation planting as a layered “garden” rather than a strip of shrubs, with the ultimate goal of nestling your home into the landscape.

Deeper foundation planting beds looks better.

Pulling shrubs and perennials away from the foundation gives extra depth and dimension to the entire composition.

Take a walk around your neighborhood and notice instances where shrubs are right up against the house. Then observe homes with shrubs planted further out. The deeper plantings look more natural and tie the house and landscape together much better.

Deeper foundation beds allow plants to grow more naturally.

It’s important to make sure that each of your plants has enough room to reach full maturity without needing to be cut back and deformed. Plants just grow better—and look more beautiful—when they have enough space.

Keep in mind that the width of the shrub you see above ground will be the same width in root growth underground. Give roots maximum space for absorbing rainwater and nutrients.

Choosing foundation plants that won’t outgrow the space

Some typical foundation evergreen shrubs that can grow too large include yews, hollies, and Mugo pines. All of these are beautiful plants as long as you have the room or can strategically prune them not to block windows.

However, a much better plan is to select plants that are going to fit your space when fully grown without the need for pruning later on. Who needs that extra maintenance? And unless you are somewhat of an expert when it comes to pruning, chances are your shrubs will eventually become misshapen.

Be cautious when buying “dwarf” varieties and cultivars of plants.

Dwarf varieties of plants can be a great solution for a foundation planting with limited space. But buyer beware! Sometimes dwarf plant revert back to the original “species” plant, and that cute little dwarf apple tree becomes too large and out of scale.

Another example is the much-loved dwarf Alberta spruce. These are the little gnome-like trees you see for sale around the holidays, potted up to use as decorations.

Dwarf Alberta spruces often appear on either sides of a front door, and they look wonderful for a while, until they start to get very large (usually at different rates of growth). The resulting lumpy large plants cover windows and just look out of place.

The term “dwarf” in this case is relative. The dwarf Alberta spruce is indeed smaller than most “regular” spruce trees, but that doesn’t mean it will remain small enough for your landscape project!

Select tried-and-true landscaping plants that are known to stay in bounds.

As ever, consulting with the staff at your most reputable local nursery will help you to choose the right-sized plants for your specific location.

These professionals have had the advantage of years of customer feedback and experience working with the plants out in the field. Most reputable nurseries will “guarantee” a shrub for one year against failure, so it’s in their best interests to guide you to the best possible selection for your site.

A landscape contractor is another golden resource. These pros go back to their customers’ landscapes year after year and get to know first-hand which plants become problematic in terms of size, and which ones they need to trim or remove.

Siting your plants based on their dimensions at full maturity

Check a plant’s tag at the nursery (or catalog listing online) for its “spread” (width) dimension. Then use a measuring tape to make sure your intended planting spot is far enough away from the foundation to accommodate the plant at full maturity.

Think of a plant as a circle, and your planting hole is at the exact center of the circle. As the plant grows, the center of the circle stays the same, but the width of circle will grow bigger and bigger.

For example, a shrub that will become 8′ wide when fully grown will need to be planted at least 4′ away from your foundation (or 6′ if you also have a 2′ “no plant” zone.)

Half of the plant will grow between the center where you planted and the wall of the foundation; the other half will grow from the center outward into the planting bed, toward your lawn.

The correct spacing might look a little strange at first, but you’ll be happy later on.

I’m a huge fan of SketchUp (free version), which is a 3D modeling software program. It’s very easy to use once you get the hang of it, and it’s a great tool from planning spacing.

Or you can use a simple sheet of graph paper and a compass to draw circles. This is a fun activity to share with your kids. I showed my daughter how to use Sketchup and plastic architects’ circle templates when she was in 4th grade, and she loved it!

Adding mulch and groundcovers to fill in open spaces between larger plants

When you have all of your main plants sited correctly in your foundation planting, there might be a lot of bare space in between them.

Not to worry, you can fill in this space using mulch, which recedes into the background and sets off your plants beautifully.

Mulch will also keep moisture in the soil for your new plants, thus reducing watering needs. And it helps to suppress weeds.

Reconsider using fabric weed barrier in your foundation planting.

Even though correct spacing of your plants might leave a lot of open space that could get weedy, resist going the landscape fabric route if you can.

There are two schools of thought within the professional landscape contractor community when it comes to landscape fabric. Some love it; some hate it.

On one hand, landscape barrier placed around shrubs and below the final mulch layer does suppress weeds. But over time, when mulch breaks down it creates a growing medium for weeds above the fabric layer, defeating the purpose.

Unless you want to commit to removing and replacing old much every year (what usually happens in commercial plantings), skip it in favor of letting your mulch break down and enriching your soil over time.

Plant groundcovers to fill in open spaces.

If you plant plugs of groundcover into your mulch, overtime these plants will spread to act like a permanent mulch for your foundation planting.

Groundcovers can add beautiful textures and color to your foundation area and can tie together all of your plants.

Groundcovers also reduce mud and splattering, keeping your foundation planting area neat in all four seasons.

Some non-invasive, earth-friendly groundcovers for foundation plantings include creeping thyme, chocolate chip ajuga, and creeping phlox.

For more groundcover ideas, check out Cornell University’s Weed Suppressive Ground Covers Brochure.

This post previously appeared on The Simple Landscape blog.


Elizabeth Douglas is the founder of Pocket Meadows. She holds a degree in landscape architectural studies and is a member of the NY State Nursery & Landscape Association.

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