How to Build a Rock Garden with Weed Prevention

Co-authored by Grant Wallace

Last Updated: December 22, 2022 References Approved

A rock garden is a good way to display plants in a natural-looking setting. Rock gardens tend to be low maintenance once you set them up and can be fit to any size yard, including small spaces or yards with natural slopes. In an area where weeds are persistent, rock gardens can also help to keep weeds down.

Method 1

Method 1 of 3:

Preparing Your Space and Preventing Weed Growth

1
Decide what kind of rock garden you want to plant. Think about the specifics of your yard. Do you want your rock garden to be a small or large one, in sun or in shade? Most rock garden plants (such as Alpines) favor sun but you can adjust your planting scheme if you have a shady site. You may want to try sketching or drawing what you want your garden to look like.^{[1]
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- Rock gardens are fairly permanent structures, so avoid placing them in spots where there are manhole covers or underground pipes that may need to be accessed.
2
Clear the site where you plan to put your rock garden. Clear your site of plants, grass and anything else that might be there, like furniture or tree roots.^{[2]
X
Research source} It might help you to plan the area if you define the edges of your rock garden by digging a ‘map’ with your spade.

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3
Plan the area’s drainage route. You’ll need to have a think about drainage and how to improve it, if your soil does not drain well. A good way to increase soil drainage is to:^{[3]
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- Remove a few inches of the topsoil. Mix in about six inches of gravel, rubble, broken bricks, pea shingle or coarse sand down. These materials will help your soil drain water more efficiently.
4
Lay weed-resistant fabric on the ground to prevent weed growth. If weeds are persistent in the area where you plan to have your rock garden, you can lay some horticultural weed-resistant fabric on the site.^{[4]
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- The fabric will allow water to penetrate but won’t allow weeds to grow through the fabric.
5
Consider laying down newspaper to prevent weeds. If you don't want to use weed-resistant fabric, lay down several layers of old newspaper above the top layer of soil. The newspaper will eventually break down but will continue to keep the weeds at bay.
- If you are worried about appearance, don’t worry—you will be laying a layer of topsoil and rocks down on top of the newspaper.

Method 2

Method 2 of 3:

Building Your Rock Garden

1
Select your rocks to create your garden. A random scattering of large and smaller rocks works well. Try to select at least two or three very large rocks to highlight your rock garden. Depending on your tastes, you may want to try to pick rocks that are all the same color and variety, as this can look more natural.^{[5]
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- Support larger rocks with bricks or smaller stones.
2
Use rocks for both visual effect and to shape your plant bed. As mentioned earlier, you can create a natural look by trying to replicate how the rocks you select would be spaced in nature. If you want something less natural and more formal looking, consider creating a frame of rocks around your plant bed. This will help to define the area you will be working in and can look quite striking.
3
Place topsoil between your rocks. Once you have your rocks in place, put a layer of topsoil in between the rocks. For an even more natural look, try to submerge the rocks in the soil so that they don’t look like they are just floating in your yard.^{[6]
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- Use weed-free topsoil. You may also want to use a topsoil that is 30% grit so that your soil drains well.
- If you are using topsoil repurposed from another area of the garden, it may not be weed-free.
4
Tread down on your soil. Press the soil into the earth and water it with a garden hose to make sure air bulbs are removed. Wait a few days before planting your garden, as your rocks may shift and settle a bit.

Method 3

Method 3 of 3:

Planting Your Rock Garden

1
Select your plants based on the characteristics of your site.^{[7]
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Research source} Keep soil type in mind, as well as whether or not the garden gets full sun, partial sun, or shade. You should also keep in mind that if you choose plants that die back during the winter, your rock garden may look rather desolate during that season. Because of this, you may want to select year-round evergreens to form the backbone of your garden.
- Lower growing, clump-forming, smaller plants work well in rock gardens, so consider Alpines and Sedums, as these plants display well against rocks. There are many evergreen Alpines to choose from. Examples include Celmisia ramulosa, Dianthus, some perennial Penstemons, and Picea.
- It’s also common to incorporate small conifers; however an Acer (Japanese Maple) is a more attractive and elegant choice for providing some height and year-round visual interest.
2
Keep in mind that some plants also work well as weed suppressors. Some plants suitable for rock gardens, such as Leptinella potentillina or Creeping Sedums, tend to cover the ground so thoroughly that they also suppress weed growth.
3
Know that rock gardens may be too dry for some plants. Large rocks have a habit of retaining heat well, so heat-loving plants will do well growing next to these rocks. Plants that need a lot of water or that don’t do well in high heat, however, may not fare as well in your rock garden.
4
Don’t feel like you have to cover your rock garden completely with plants. Many gardeners aim to conceal visible ground or soil when planting a bed. Rock gardens are different because the aim is to display the background rocks as well as the plants themselves. For this reason, you don’t need to cover the rock garden completely with plants.
- Ideally your rock garden plants should spread slowly, so give your plants space to grow.
5
Care for your rock garden. While many rock garden plants tend to be very independent (which means they don’t require that much water) you may want to spend some time weeding your garden every few days. Weeds will be less of a problem if you chose to put down newspaper or organic fabric as described in Method 1.
- You may also find that ants can be a bit of a pest as they may set up their home in between your rocks. If you are alright with this, leave them be. If you’d rather not have them around, ant killer can be purchased at your local garden store.

Community Q&A

Question

Could I cover the soil with plastic cover for the weeds not to come through?

Community Answer

Yes. You can always layer on some more rocks and plant some succulents or small plants.
Question

What are good plants to put in a rock garden?

Community Answer

Small or decorative plants, such as cacti and succulents are perfect to put in a rock garden. They make the garden look aesthetic (if that's your aim) and can prevent any unwanted weeds from poking through.
Question

Is there anything besides newspaper and fabric to prevent weeds? Anything non-permeable?

Community Answer

It depends where you are using it. I use offcuts of synthetic carpet to make paths in vegegi beds or under gravel/cobbles if not planting through it.

Warnings

Be careful not to damage your back lifting heavy materials. You may need help to put the larger rocks into their places.

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