Adding Boulders to your Landscape

Are you thinking about including rocks and boulders in your landscape? If you’ve started researching boulders for your landscape, you’ve probably come to appreciate that a rock isn’t just a rock. There is a lot to consider when choosing rocks for your project, and we want to help. Whether you’re a homeowner with the DIY bug, or a contractor or landscaper wanting to learn more about how to use boulders, we’ve collected all the information you need to get started.

What is a boulder?

A boulder is defined as any rock larger than 16” in diameter. Boulders are available in two basic shapes: round and angular. 

  • Round boulders have smooth edges and curves. They are water-washed or river-run surface stones of granite and sandstone, worn over the eons by wind, sand and rain. 
  • Angular boulders have jagged, blasted edges and flat faces. They are columnar, boxy or rectangular and may be composed of but not limited to granite, quartzite, sandstone and basalt.

Boulders are more colorful than you’d think!

Choosing the Color of your boulder may be the hardest part of the process. Most people aren’t aware of just how many colors are available for boulders. Pink, gold, brown, gray, tan, green and every combination in between…at Southwest Boulder we have boulders in dozens of colors. 

To make things a little easier, not all colors are available each style (round/angular), so finding a combination of colors and shape that suits your needs will narrow your choices. Need a place to start? In our 25 years in the industry, the most popular boulders at Southwest Boulder & Stone have proven to be Gray Cresta, and Sierra.

What size boulder should you use?

This is may be the most important factor to consider. Here’s the problem: if the boulders you choose are too small, they may be lost once surrounding plant material reaches its mature size, or your boulders may look insignificant compared to other features of the landscape.

And it gets worse - if you choose boulders that are too big, they may dwarf other landscape features or just look out of place.

So how do you determine what size boulder will work best for your landscape? Here’s the solution:

There’s a simple way to “size up” your landscape rock. Before going out to a rock yard to choose your boulders, fill plastic trash bags of various sizes with crumpled newspaper creating “boulders” of the size you think would work into your landscape design. Place these in the areas where you want to use the boulders. This will give you a good idea of how different size boulders will look in scale, as well as how many boulders you need and where you want them placed. And they are a lot easier to move around than real boulders! You can shift, roll, tweak and perfect the placement and size of all your boulders before things get “heavy.”

Placing boulders for a natural look

Just as important as the color and shape of your stone is a natural look of stability and permanence in your garden. Using odd numbers of boulders, combining different sizes of boulders, and placing your biggest boulder off-center in your yard will achieve the most natural look.

Landscape Design Pro Tip

Place your boulders in odd numbers and groupings. Avoid symmetry and vary your sizes for a more natural look.

Another great way to help your boulders blend in with the landscape is to dig down a bit to place approximately 1/3 of the boulder below ground level. While this isn’t a hard and fast rule, it will add to the impression that your boulders are laying naturally in the soil instead of sitting on top of it.

How do you get boulders into your yard?

Once you’ve determined the shape, color, size and quantity of your boulders, Delivery and Placement is the next question. If the boulders are small (generally less than 2 feet in diameter) you may be able to use your own truck and a wheelbarrow or a heavy-duty dolly. We call them “Rock Dollies” at Southwest Boulder & Stone, and we often rent them out to homeowners doing DIY installations. They resemble appliance dollies, but are bigger and designed to move trees. But beware - boulders may be even heavier than you thought:

A granite boulder weights approximately 165 lbs per square foot. That “little” two-foot boulder could weigh between 400-500 lbs!

For larger boulders, and sometimes even for smaller ones, we recommend using a professional to help you install them in your yard. Small tractors and forklifts are usually available through a local contractor, and some rock companies even offer heavy-duty cranes to deliver and place the boulders in your landscape, twisting and turning each piece to meet your exact specifications. Inquire at the rock yard where you plan to buy your boulders – they will have the best information and resources to deliver your boulders to you. If you are considering Southwest Boulder & Stone as your boulder supplier you can find more information on our stone delivery options here, or call us at 877-792-7625.

You’re ready to install boulders!

Now that you know all about the types, colors and sizes of boulders and have a good idea of how to plan and place them, you are ready to plan a visit to a rock yard near you to pick out the perfect stones for your project. We wish you the best of luck with your boulder installation, and let us know in the comments if you have any questions. We’d also love to see pictures of your finished boulder landscape if you’d like to share them with us. Have fun!

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