Combatting Erosion: Installing Rock Terraces and Swales on Sloped Yards

Montana’s natural landscape is filled with rolling hills, rugged terrain, and beautiful slopes—but these features often come with a frustrating downside: soil erosion. If your yard sits on a slope or hillside, spring runoff and seasonal rain can carry precious topsoil downhill, wash out plants, and leave deep ruts that disrupt both function and beauty. Fortunately, there’s a proven solution that’s as effective as it is attractive: installing rock terraces and swales.

At Horizon Landscape & Irrigation, we help homeowners in Billings and beyond control erosion on sloped properties with natural hardscape features that blend seamlessly into the landscape. Rock terraces and swales are two of the most trusted methods for slowing water flow, capturing runoff, and maintaining a healthier yard—especially in Montana’s unpredictable climate.

1. What Causes Erosion on Sloped Yards?
Erosion happens when water moves across exposed or loose soil, carrying it downhill. This is especially common on sloped yards where gravity increases the speed and volume of runoff. Without anything to slow that flow, soil is stripped away, grass struggles to grow, and landscaping becomes nearly impossible to maintain.

In areas like Billings, spring rains and snowmelt contribute heavily to erosion. Even with good drainage, a steep yard needs the right structural support to keep soil in place. That’s where rock terraces and swales come into play.

2. Rock Terraces: Natural Retaining Walls with Style
Rock terraces are layered retaining walls made of boulders or natural stone that create level planting areas on an otherwise steep slope. Each terrace acts as a barrier, catching water and encouraging it to soak into the ground rather than running downhill.

Benefits of rock terraces:

Stability: Stops soil from sliding or washing away.

Plant-Friendly: Each level can be filled with nutrient-rich soil for native plants, shrubs, or even vegetables.

Curb Appeal: Natural stone creates a rustic, beautiful feature that blends into the Montana landscape.

Low Maintenance: Once installed, terraces require very little upkeep compared to loose slopes.

Our team designs custom terraces to suit your yard’s size, slope, and soil type. Whether you’re going for a wildflower rock garden or a neatly stacked look, we can shape your slope into something both practical and eye-catching.

3. Swales: Directing the Flow the Smart Way
While terraces hold soil in place, swales are designed to redirect water in a controlled way. A swale is a shallow, vegetated trench or depression that collects and channels runoff—guiding it away from your home, garden beds, or problem areas.

Benefits of swales:

Erosion Control: Slows down water, spreads it out, and gives it time to soak into the ground.

Water Conservation: Helps recharge groundwater and supports surrounding plant life.

Customizable: Swales can be natural-looking with native grasses or enhanced with decorative rocks for a polished look.

In many cases, we install swales at the base of terraces or along natural drainage paths to give water a safe place to go. They can also be combined with dry creek beds for added beauty and function.

4. The Best of Both Worlds: A Hybrid Approach
Terraces and swales don’t have to be either-or solutions. In fact, the most effective erosion control plans usually combine both. Terraces help slow water and prevent downhill rushes, while swales manage the water that still makes it through. Together, they form a system that protects your soil, supports healthy growth, and keeps your landscaping investment in place for years to come.

Our team at Horizon will assess your property’s slope, soil conditions, and drainage needs to design a layered solution that works naturally with your yard—not against it.

5. Installation and Maintenance Tips
Here are a few tips to consider before installing rock terraces or swales:

Start at the Top: Erosion control works best when it begins where the water starts flowing.

Use Native Plants: Montana-friendly grasses and shrubs can take root easily and hold soil better.

Layer Smart: Allow for proper drainage between terraces to avoid pooling or oversaturation.

Keep It Natural: Let your slope follow its natural contour—overengineering can create more problems than it solves.

Once installed, rock terraces and swales require minimal maintenance. Just check occasionally for shifting stones, debris buildup in swales, or plant overgrowth that may obstruct water flow.

Tame Your Slope, Transform Your Yard

Living on a hill doesn’t mean you have to surrender your landscape to erosion. With the right blend of rock terraces and swales, you can take control of your yard’s water flow while adding lasting beauty and function. Whether your slope is slight or steep, Horizon Landscape & Irrigation has the tools and experience to help you protect your soil and make the most of your outdoor space.

Contact us today to schedule a slope assessment and see how natural hardscaping can give your yard the edge it needs. Learn more at https://horizonlandscapemt.com.