Sloped rock garden ideas

Planting a Hillside Rock Garden

By The National Gardening Association, Bob Beckstrom, Karan Davis Cutler, Kathleen Fisher, Phillip Giroux, Judy Glattstein, Michael MacCaskey, Bill Marken, Charlie Nardozzi, Sally Roth, Marcia Tatroe, Lance Walheim, Ann Whitman

Instead of viewing a slope in your yard as a landscape liability, consider it a great opportunity — a place to display a rock garden. Rock garden plants are quite beautiful, and growing them on a slope near a walkway gives you the opportunity to view them up close.

Your rock garden plan could combine plants, steps, and boulders — and can work in the backyard at the edge of a lawn or in front, right off of a sidewalk.

Keep the following in mind for creating this sort of rock garden:

  • The steps are stones. Use stones of different lengths for a more natural look. Choose stones with a smooth, flat surface, and put them in place firmly. Create planting pockets on the steps.
  • Riprap (large chunks of rock) helps the soil. Randomly stacking rocks of varying size is an economical way to retain soil on the slope — the steeper the hillside, the closer together you want the rocks to stabilize the soil effectively. Add planting pockets between the rocks to soften harshness.
  • Boulders add a natural touch. Keep them in scale, not too big or too small for the site.
  • Color and texture come alive. Typical rock garden plants are small and slow growing, offering a variety of textures that are best viewed close up. For color, include blooming perennials, such as lavender, coreopsis, and salvia.
  • Small trees and shrubs add beauty. Potential rock garden trees include dwarf arborvitae (Thuja occidentalis), dwarf hemlock (Tsuga canadensis), dwarf hinoki cypress (Chamaecyparis obtusa), Japanese maple (Acer palmatum), and Mugho pine (Pinus mugo mugo). As for shrubs, try bog rosemary (Andromeda polifolia ‘Nana’), dwarf heath (Erica), dwarf Japanese holly (Ilex crenata), dwarf junipers, and dwarf Scotch heather (Calluna vulgaris).
  • Small perennials bring bursts of color. Perennials that work well in a simple rock garden include bellflower (Campanula), Cranesbill (Geranium), Moonbeam coreopsis (Coreopsis verticillata ‘Moonbeam’), primroses (Primula), thrift (Armeria), thyme (Thymus), and Yarrow (Achillea).

Lessons from The Hills: Gardening on Rocky and Steep Slopes 

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  • Larry Decker
  • A rock garden in The Hills.

Rock in Them Thar Hills

The Hills neighborhood of Port Ewen was created in the mid-1980s by blasting bluestone outcroppings that overlook the historic Rondout waterfront in Kingston. Nearby is a bluestone quarry, one of many that provided the principal material for the construction of New York City’s sidewalk system in the late 19th and early 20th century.

The first home buyers in The Hills encountered a beautiful blue-gray rocky moonscape; it was up to them to build lawns among the rocks and on top of bedrock. The landscape is also steeply sloped in many places; prospective gardeners have had to reckon with the eroding pull of gravity on the soil that they brought in.

Original homeowners Joe and Candy Erena looked at the pile of rocks the developer had deposited outside their home and decided to create a rock garden among them. That was 27 years ago, and they have learned a great deal by trial and error, especially about which plants can survive the harsh conditions. A few doors up, their friends Françoise and Alan Dunefsky were simultaneously working with a steep backyard that dropped precipitously into rocky woods. Françoise says that the first year, she brought in a $600 truckload of topsoil. When the snow melted the next spring, all of the carefully laid soil had slid over the embankment and into the woods. After that, she began putting in terraced gardens, lined with indigenous bluestone, to help stabilize the soil.

Newer residents of The Hills like Jim and Marianne Crist and neighbor Rick Foster have been able to learn from the experiences of the Erenas and the Dunefskys. In tackling the challenges of their site, a bond has been forged among the neighboring gardeners, and the series of gardens reads like shared parkland. These gardeners have things to teach anyone approaching a rocky or simply steep slope and wanting to enhance its beauty while keeping the precious soil in place.

Before You Plant

Gardening on a rocky slope can be a big commitment, because gravity will challenge the gardener, the rocks, the soil, and the plants. For instance, slopes tend to be dry, so plants must be drought-adaptable, and provision must be made for watering. The rocks, even big ones that seem fixed in place, can shift downwards. If you disrupt indigenous/existing vegetation to make your garden, you have to be careful not to create more erosion in the process. On the plus side, rocky slope gardens can be gratifying aesthetically, because plants and rocks are showcased more individually and more dramatically on a slope than they would be in a flat border.

Rick Foster says that whether building a garden around existing rocks or creating something new by bringing in rocks, the first step is to spend time just observing. “The rocks should look pleasing to you with nothing else,” Foster says. “This is what you’re going to look at all the time, especially in winter. It’s worth spending a year to first just enjoy the structure of your rock outcropping and/or the rock garden you built. Then eventually you will start to envision certain plants in certain spots.”

The next step is to create safe and aesthetic points of access and to terrace the land if the soil is likely to erode. For neighbors Foster and Jim Crist, bluestone rock steps allow entrance to the terraces of the slope behind their homes. In placing the steps, Foster used rocks he found in the woods, and he endeavored to create a pleasing garden focal point that is also stable. Then came the soil-preserving terraces, which Crist says also provide a safe place to work standing up on relatively flat ground. (Before the stairs and terraces, there was only a jungle of overgrown vegetation that Crist was at a loss at how to approach.)

As with any garden, your rocky slope garden or terrace needs good soil preparation. In The Hills this usually means building up the soil with compost, because the bedrock is so close to the surface. However, there are limits to how much soil will remain. When Joe and Candy Erena started to create their rock garden out of the pile of rocks they inherited from the developer, they found that little soil was present. They did their due diligence and brought in topsoil.

“It just disappeared through the cracks,” Joe Erena says. “We’d add soil and plant Japanese maple trees; they would do well for a few years then die.” This was because the tree roots inevitably ran out of usable rooting volume, then the trees declined as though they were pot-bound. The trees became root-bound and desiccated even though the Erenas faithfully watered them (if you’ve ever tried to keep a tree in a pot for any length of time, you know how quickly and stubbornly the pot-bound roots dry out).

Planting Trial and Error

Eventually, the Erenas let go of their original planting scheme (e.g., Japanese maples) and stepped back and observed which plants volunteered in/migrated about the garden (volunteers are happiest). For instance, a white cedar found purchase on the rock, and they decided to embrace it. Originally, Candy Erena would put in annuals every year, but that was very labor-intensive, so she moved to perennials and to selectively retaining volunteers. “The rock garden changes every year,” she says. “I’m always surprised and think: where did that come from? Every five years it’s a completely different garden.”

Some of the volunteers the Erenas have embraced on their rock garden include Siberian irises, hostas, myrtle, daylilies, wild columbine, and wild chives. Creeping phlox, sedum, hens and chicks, and ferns are among the plants that grow right out of the rock, with scant or seemingly no soil. Candy Erena says, “Avoid planting something potentially invasive because it’s easy for those plants to take over a rock garden, because they so quickly out-compete the more delicate plants.”

Françoise Dunefsky, Rick Foster, and Jim Crist have found that colony-forming shrubs—those that spread via underground stems and other means to send up new shoots (suckers) in a widening band—are especially useful for soil stabilization. These include forsythia, sweetshrub, flowering quince, old-fashioned lilacs, rugosa roses, deutzia, and red- and yellow-twig dogwood. Ornamental grasses are also useful because of their very tenacious root systems.

In Françoise Dunefsky’s case, for her gardens on the steepest part of her property, she had to sacrifice sunny conditions. “I learned over 25 years that I had to make a marriage between certain trees and shrubs and that rock garden,” she says. “I needed trees and shrubs for their root systems to help hold rocks and soil in place.” Thus those gardens became shade gardens over time, necessitating some adjustment in the kinds of perennial plants used among the trees and shrubs.

It’s difficult to have a rocky or steep slope garden that is low maintenance. Because they tend to be so dry, slopes and rock gardens need a lot of water, by hand or with sprinklers or drip irrigation. Debris cleanup can be tricky because it’s not easy to rake among rocks. Candy Erena spends four to five hours a week in spring doing cleanup and two to three hours a week in summer keeping the beds weeded and relatively free of debris. “I really enjoy it, and I follow the shade, because it gets hot in a rock garden,” she says.


Landscaping Steep Slopes

Deciduous Woody Groundcovers

21 Landscaping Ideas for Slopes – Slight, Moderate and Steep

Turn that boring slope into something beautiful…

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IS YOUR BLOCK ON A slant? These 21 landscaping ideas for slopes will help you turn your sloped yard into the envy of your flat yard friends and family. Sloped yards naturally help break up the different spots in your yard, and these landscaping ideas for slopes help accentuate that.

Slight Slopes

Image courtesy of Pinterest

1. Becoming a “Rock”(et) Man

Okay, so terrible pun, but the way this person used rocks to create a flat spot in their sloping yard for a small patio deserves recognition. The rocks help hold back the extra soil needed to create the patio and the mulch keeps soil erosion under control.

Image courtesy of Pinterest

2. Layering at Its Finest

Just because you have a sloping garden doesn’t mean you can’t do something different with it. Using paving bricks to created multiple tiered gardens and a nice gently set of steps takes what was probably an unused area of the yard and creates something beautiful and functional out of it.

Image courtesy of Pic2Viral

3. Just Slab It Together

Yes, you can buy large slabs of rock just like these from a local distributor. Finding them is easy, the hard part comes in getting someone to help you lay them perfectly going down the slope in your backyard. But you will find as you sit by the firepit that the expense and effort are well-worth it.

Moderate Slopes

4. Holding It Back with Bricks

In this particular case, it looks like someone carved out a nice flat space for a small deck and flower gardens. Lumber was then used to create a retaining wall to hold back the rest of the slope. The tiered slope also provides a windbreak for whoever is sitting in the chair.

5. Keeping It All in Place

Dealing with a moderate slope can be easy if you use pavers to create the retaining wall as seen here. Note how the homeowner has built in a set of steps that allow everyone to get up into the rest of the yard. The trees and shrubs also help keep the soil in place.

Image courtesy of Pinterest

6. Gardens at Every Level

This yard features several tiers of gardens held in place using natural rock walls and steps. Natural rock like this is available at many DIY home and garden centers or if you are really lucky, you can go out and forage for them yourself.

7. Climb Your Way to the Top

Rather than focusing on the fact he has a sloping yard, this homeowner not only terraced his yard, he took the time and effort to build stairs to help everyone master the slope. Plus, he added a handrail that runs all the way to the top.

Steep Slopes

Slope Erosion Control Grids

8. Slowing Progress Down

In many ways, progress is a good thing, but when it comes to that steep slope in your backyard progress is not a good thing when all the soil starts washing away. This homeowner made use of custom plastic mesh to hold back the advances of time. You could fill the mesh with soil and plant grass, ground cover, or even flowers.

Image courtesy of Triyae.Com

9. The Modern Look of Cement

Here the homeowner has used cement to create a modern tiered look to make the most use out of what might otherwise have been wasted yard. Adding the step lights turns this part of his yard into a late evening paradise.

Image courtesy of Farnsworth

10. Create Your Own Cliff

Not everyone gets to have their own personal cliff in their backyard. It looks like this yard had a nasty drop off the owner used to create the look of mountain cliff by using the structured planting of trees in the back and shrubs up front. Using rocks and slabs for the steps keeps the illusion alive.

Image courtesy of Pinterest

11. Truly Layered Beauty

Mowing down a slope this steep would be no fun at all. So instead the owner planted gardens in all the areas he couldn’t or wouldn’t mow. The staggered stairs stop at garden level for maintenance. That small beach would be a great place to relax in the sun.

Image courtesy of Pinterest

12. Clambering Down the Mountainside

It almost looks as if this person liked the idea of clambering down the side of the mountain. The rock steps provide safe passage even when wet and the guide ropes give it all a nice rustic look. He also used plenty of very large rocks to help hold the slope in place.

Image courtesy of Pinterest

13. When Did We Move Out to the Country

Although you can see the neighbor in the background, this homeowner turned his steep slope into his own personal forest with the judicious use of many different shrubs and plants of all sizes. Even the haphazard wood and gravel steps look like something you might find in a state or national park. (Hmm wonder if he’s a park ranger)

Image courtesy of Pinterest

14. Climbing the Stairway to Heaven

Making this incredible stairway from lumber and gravel is a good way to provide plenty of non-slip passage up this steep slope. The wicker handrail and adds an incredible back country look to this lovely yard.

Image courtesy of Pinterest

15. It’s All Fun and Games

This person took what many would see as useless and turned it all into something angular and beautiful. Not only did they add seats for the whole family, they also built in a slide for the little ones so they could enjoy the slope.

Image courtsey of Pinterest

16. Not All Slopes Are Straight

This slope has a bit of a curve in its slope. Making it the perfect place to create a scenic curved staircase made from slabs cut out of local rock. The carefully placed boulders also help to keep everything in place.

Image courtesy of Pinterest

17. Raised Garden Beds Can Feed the Family

This homeowner made great use of this slope to create terraces for his raised garden beds. The concrete walls keep everything nicely in place and there is a great place in the shade for the family to relax.

Image courtesy of Pinterest

18. Amazing What You Can Do with Railroad Ties

People have been using old railroad ties to create strong steps up steep slopes like this one for decades. Using ground cover plants is a great way to stop erosion and add a ton of color to what might otherwise be a boring slope.

Image courtesy of Pinterest

19. Follow the Garden Path

When life hands you short steep slopes throughout your backyard, you use them to create a fun path through the gardens. It looks like this homeowner hand-laid the rock walls, this style of building a wall is a lost art. The heavy use of mulch helps to keep the gardens in place and create a wonderful color palette.

Image courtesy of Pinterest

20. Welcome to Boulder City

This stairway made from slabs of granite and mini-boulders almost looks like it was made by mother nature. But look at the trellises lining the side that can be used for climbing flowers, vines, even veggies. (I love the idea of growing peas and picking them as I walk up these stairs)

Image courtesy of Pinterest

21. Ignore the Stairs

While these railroad tie and gravel stairs are certainly impressive, that’s not what makes the owner’s use of this slope so cool. It’s the raised flower beds that climb up beside the steps that make it so amazing. Imagine what walking up or down them when all the flowers are all in bloom.

There’s no doubt that landscaping a hillside requires more effort than a flat garden. That doesn’t mean your hillside landscaping ideas can’t be exciting. In fact, there are a ton of ways to fabricate a beautiful scene out of your sloped yard which would even overshadow a flat garden.

Yet, a sloped yard introduces some challenges. A hillside yard is much harder to maintain than a flat one. The main problem is that soil tends to run off and down the slope. This largely depends on how steep the slope is and the climate. A slope ratio of 3:1 or less is considered ideal and it should be easy to grow plants in it. A more extreme ratio, like 2:1 or more, is harder to deal with and planting would require extra care and maintenance. Another problem with sloped yards is that walking on a hillside can be exhausting and difficult.

Additionally, extreme weather conditions such as heavy rain may cause the slope to fail. When rain falls on the slope, soil particles gradually dislocate and fall off causing erosion. Your best bet for hillside landscaping ideas is to use woody plants that have deep fine roots. You can also use rocks to slow down the runoff. Another thing that probably crossed your mind is that walking on a hillside can be exhausting and difficult.

The types of plants you’re going to grow is also an important thing to keep in mind. Some plants grow perfectly on slopes while others wash down easily with rain. Plants that are suitable for slopes hold the ground pretty well thanks to their strong network of roots. Shrubs are a popular choice for growing plants on hillsides.

Anyway, we’ve got your back. We’ll give you some awesome ideas that can inspire you to transform your yard while also addressing the problems that you may face.

A Rock Garden on a Hillside

A great procedure to prevent the plants from washing down the slope is to use large rocks to anchor the soil. This way, the plants can hold in place till they grow. Spread the rocks randomly to give your hillside a more natural look. Maintenance might be required frequently in the early stages but once the plants spread out more, minimal maintenance would be required. This is a good alternative to creating flat areas for planting.

A Hillside Flower Garden

Emphasizing planting flowers in your hillside garden will add life and beauty to the scene. You can grow a variety of flower types and colors in even quantities. You’d also want to vary the growing height of the flowers on each level. Fragrant sumac, California lilac, Japanese yew, and creeping juniper are all beautiful plants that grow nicely on slopes.

Gardening a Yard Sloping Down the Road

While having a house that’s located on a hill is a beautiful thing as it can give you a spectacular view, sometimes this means that your yard’s slope ends at the side of a road, creating a hell strip effect. In that case, you’d have to opt for plants that don’t require extensive maintenance and cutting. Evergreen plants would be a good choice. They look lovely on their own and they don’t require frequent grooming. If you don’t want to completely block the view with high growing plants, you may want to use lower growing perennials for the front row.

Landscaping a Hillside using Planters

What about using planters for your hillside garden? Planters make your garden much easier to maintain. They’re especially useful for slopes that are too steep since you obviously won’t have to worry about the soil running off. Over and above that, they also make watering the plants more convenient. You can also create a garden room at the lower level.

Using Stairs for Steep Slopes

Is the slope of your yard too steep? If that’s the case, you need stairs. There are a variety of materials you can use to staircase your yard. Stone, wood, and steel are all good options for that. Stone stairs are probably your best bet because they are tough and will almost never wear out. You might also consider taking extra care of the area around the sides of the stairs to give your hillside a more pleasing scene.

Creating a Beautifully-Shaped Garden

What about something a little out of the ordinary? Instead of just randomly planting the flowers, you can plant them in a way that produces neat shapes when you’re done. You can create square shapes like in the pictures but there are other options too like circular and spiral shapes. This will add a form of symmetry to your garden which will make it quite appealing to look at. You can mix up the colors of the flowers or you can go unicolor too. Yellow would be great in case you decided to use one color.

Approaching the Slope

The approach of a slope is just as important as the slope itself. In this design, the path to the slope is surrounded by plants and retaining walls. Adding a resting spot such as a bench can really polish up the design while also offering a breather before going up the stairs. Sophisticated plants such as roses, coralbells, and hostas provide a beautiful and unique visual appearance.

Terracing a Fruit Garden

A hillside is a very suitable environment for a fruit garden, especially if the slope is facing towards the south. Drip-irrigation would be an ideal option for such a garden as it could be difficult to provide the garden with water and supplies. You can level and terrace your garden such that each row of plants will receive direct sunlight without getting shaded by another row. You can also make use of the raised ground to plant some roses and other flowers as they will be easily viewed, creating a beautiful scene while also making good use of the garden.

Ground-covering on a Hillside

If you’ve got a gentle slope or berm that links a wood-covered area with your open yard, you can create a seamless transition using groundcovers that will look like a colorful mat. However, keep in mind that soil drainage is much faster on a berm. You can maintain it just like you’d maintain a rock garden. Some of the plants you can use are alpines, tiny bellflowers, creeping phlox, and perennial geraniums.

Making a Garden Walk out of your Hillside

What would be more beautiful than turning your hillside yard into a garden walk? You can easily accomplish this by terracing a walkway using stepping stones. You can then put some plants along the walkway and voilà! You’ve got yourself a garden walk in your yard. Gradually elevating the planting area as you climb up higher on the walkway would also be a great idea to really accentuate your garden walk. You can use pots for decoration at the beginning of the path.

Using Rocks to Staircase Your Yard

Don’t want to use artificial looking stairs for your hillside yard? Try using rocks instead. This will give your hillside yard a zen look and feel. You can also add some plants around the stones as they act as a natural anchor for the soil that prevents runoff.

Terracing by Using Stone Walls

Stone walls are a popular method for taming and terracing hillsides. They may seem like they require a ton of work and while that holds true in the initial phase, once you’re done with the walls, you’ve got yourself a garden that both looks beautiful and is also easy to maintain. You can establish wide planting areas where you can grow plants that would be harder to grow outside of these walls. Additionally, since stones can easily heat up in hotter weathers, this will be quite beneficial for the plants to grow as the stones will create what’s known as a microclimate.

A hillside Garden With Low Maintenance Plants

Runoff is one of the major problems that can face you with hillside gardens and even more so when the slope ends with a driveway. One way to solve this problem is to use plants that will anchor the hillside by forming a network of roots. Some of these plants are ornamental grasses, shrubs, and coneflower. All of these plants will prevent soil runoff and require very little maintenance when they’re growing. Moreover, you can leave them standing during wintertime. Think carefully when you’re choosing which plants to grow. This way, a hillside will be the highlight of your yard and even your whole home.

Planting Shrubs in Your Yard

Shrubs are an excellent choice for your hillside yard. They require little to no maintenance in addition to looking beautiful and colorful. They are not easily affected by erosion too. They look great all year round. All you need is some pruning during springtime and you’ve got yourself a garden that will look good for the remaining time of the year.

Using Curves for Your Hillside Yard

Forget stairs. You can level your hillside yard using a curved path that takes a spiral shape. This would be especially suitable if your yard is too wide without being long enough and with a slope that’s not too steep. It’s also a great idea if the entrance to your yard is from the side of your home’s door. You can carpet the path with grass.

Adding Water to the Slope

This is another interesting idea for landscaping your hillside yard. Have you ever thought about creating a waterfall in your yard? It’s one of the perks of having a sloped yard. Using water will add motion to the scene, creating a beautiful dynamic view. Moreover, the sound of the water will create a soothing and relaxing atmosphere in your yard. Furthermore, putting some lights into the water will make your yard look even more beautiful and lively at night. Growing some evergreen plants around the waterfall will also add a natural feel to the hillside. The steps of this garden will slow down the water flow. The waterfall can also be used for irrigation which will actually make your garden more functional and you can also use horizontal beams instead of steps.

Modern Garden on a Hillside

If you’re a fan of contemporary decorations, you might consider going for a cement-stepped hillside garden. This would look quite luxurious especially during night time when you turn on the lights. The symmetry will create a pleasing view and the cement will also double as planting boxes that you can use to grow all the plants you want without having to worry much about runoffs. It’s another great idea on the list for taming your sloped garden while also benefiting from a sophisticated view.

Wrap Up

Hillside landscaping ideas involve a lot of exploring and experimentation; it can really trigger your creative thinking. There’s a lot you can do with your hillside yard. You just have to choose what seems to fit your yard the most according to the available space and how steep the slope is. You can also borrow a thing or two from multiple ideas to create your own unique hillside yard. Just make sure to keep the problems/drawbacks that were mentioned earlier in mind and you should be good to go.

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