To build a rock border or wall around your garden, first select the rocks that appeal to you. Then, excavate a 3–5 inch (7.5–13 cm) trench around your garden. Lay mulch or landscape fabric in the trench to prevent weeds from coming up among your garden border. Next, place your rocks, stacking them carefully if you’re building a wall. Finally, water the rocks and soil beneath, then tamp them into place.
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Tools Required for Building a Rock Garden Border
Building a rock border for your garden is a simple DIY project you can tackle yourself. It requires very few specialized tools. The equipment you need for this job includes:
- Landscape fabric
- Tamper or mallet
- Hammer and rock chisel (if you’re shaping rocks for a wall)
We’ll cover how to shape large, flat rocks for a garden wall below. If you’re stacking or laying stones without shaping them, you won’t need a hammer and chisel.
5 Steps to Build a Rock Garden Border
Before you begin, plan out the design of your garden border. Calculate how many feet of the border you’re laying. Then, decide whether you’re laying one layer of rocks or stacking them into a small wall. This will help you determine the amount of materials you need. Then, you can begin.
Choose Your Rocks
Are you laying a single row of rocks pressed into the dirt to create a garden border? If so, rounded river rocks or quartz are attractive choices. Are you building a small garden wall of stacked stone? Choose a flat type of stone, such as slate, flagstones, or fieldstones.
- Choose larger, rounded stones for an effective single-layer garden border.
- Flat stones are best suited for building a small rock wall border.
Different varieties of rocks for your garden can be found at a local hardware or garden center. However, you may be able to get a better price on garden stones at a landscape supply wholesaler.
Dig Your Border Trench
Use your shovel to dig a trench 3–5 (7.5–13 cm) inches deep along the edge of your garden. Make certain the trench is wide enough to accommodate the stones you plan to lay.
- Dig a 3–5 inch deep trench where you plan to lay your rock border.
- If you are stacking rocks for a garden wall, make sure the floor of the trench is level. Due to yard slope, you may need to dig deeper in some areas than others.
By creating a uniform, level border trench, you make the following steps easy and will end with an attractive border that won’t be easily disturbed or displaced.
Lay a Weed-Stopping Barrier
Few things are more frustrating than weeds growing up through your rock border. They can ruin the look of your border and weeds in rocks are especially hard to kill. In order to prevent your garden border from becoming overrun with weed growth, do the following:
- Line the trench with this water-permeable landscape fabric.
- Cover the landscape fabric with 1 (2.5 cm) inch of mulch, to hide it and protect it from being punctured by the rocks.
It’s important to use water-permeable landscape fabric in all your landscaping applications. Sheets of plastic are a poor alternative because they cause water to pool, creating breeding grounds for mosquitos and other pest insects. Keep your garden weed and bug-free with the right materials.
Place Your Rocks
Now that your border trench is dug and lined with a weed-resistant layer, it’s time to place your rocks. With several methods to choose from, you can decide for yourself whether you want rocks laid in a single layer, arranged in a design, or stacked to create a low wall.
- Lay rocks in a single row, create a design, or stack them to build a garden wall.
- Make a continuous border without gaps to keep mulch in your garden and keep grass out.
Place rocks so that each one touches its neighbors. A landscape border is most effective at keeping mulch in and grass out when it forms a continuous boundary. We’ll go into more detail on building small rock border walls below.
Make Sure Your Border Stays Put
Rocks should be set partway into the soil to prevent them from becoming dislodged and ruining the look of your border. In order to get your border rocks to stay in place, follow these steps:
- Spray the border area with water from your hose, enough to dampen the soil but not turn it to mud.
- Use your mallet or tamper to gently tap rocks into the soil deep enough that they are solidly in place.
- Do not hit rocks too hard, to avoid breaking them or tearing the landscape fabric below.
Once you have set all the rocks into place, allow the soil to dry and check your rock borders. Rocks that remain firmly in place when touched are set. Any that wiggle easily may need to be re-wetted and tamped into place. Once you’ve got all your rocks seated firmly in the soil, your work is done and your garden border is complete.
How Do You Stack Rocks for a Border?
Lay rocks in an overlapping fashion to build a rock wall around your garden. As long as the wall is 18 inches or lower, you don’t need to mortar it in place. Mortar may make for a sturdier wall, but it also makes changing your garden border a monumental task. When planning to build a stacked rock wall, do the following:
- Dig a level trench.
- Shape any oversized rocks to make them suitable for stacking.
- Lay rocks in an overlapping pattern to help them “lock” together.
- Backfill rock wall with dirt and mulch to provide stability.
One trick for making sure your wall doesn’t topple is to build it with a slight backward tilt. Then, backfill the area behind the wall with dirt and mulch. The backfill dirt behind the wall will keep the rocks in place. Because the wall is leaning slightly back against the backfill dirt, this eliminates the chance that it will fall forward.
How to Shape Rocks to Build a Border
If you are building a stacked wall border, you need the right type of rock for the job. Usually, these are flat fieldstones, flagstones, or similar shale-type rocks. Sometimes, they aren’t the right size to fit. If you need to shape rocks to build a wall, follow these steps:
- Wear eye protection to protect yourself from stone chips.
- Measure and mark where you wish to cut off a piece of rock to shape it.
- Use a rock chisel and hammer to score along the line you marked.
- Continue to score the line more deeply to break the stone along this line.
If you intend to shape a large number of rocks for a garden wall, consider investing in a chisel attachment for your reciprocating saw, or use a circular saw with a blade intended for cutting stone. For small projects where you only need to shape a few rocks, the hammer and chisel method is all you need.
How to Build a Stone Flower Bed Border
To create a border of attractive rocks around your garden beds, simply follow these steps:
- Choose the right rock for your border, depending on the design you’re going for.
- Dig a 3–5 (7.5–13 cm) inch deep trench along the edge of your garden.
- Line the trench with landscape fabric and cover with 1 inch (2.5 cm) of mulch.
- Lay the rocks, or stack them to create a small rock wall.
- Water the soil around the border and tamp the rocks into place.
It’s amazing what a simple arrangement of rocks can do to transform the look of a yard. Rock borders are attractive, easy to maintain, and functional. A rock border helps keep mulch inside your garden and prevents weeds and grasses from easily spreading into your flower beds. This simple project is well worth the effort.