How to Make a Rock Garden

When you think about a garden or landscape, most people picture green lawns, vibrant foliage and colourful flowers. Few people think of rocks. However, the fact is, when done properly, rock features are a fantastic way of spicing up your lawn and making the most of areas of your garden that you have found difficult to maintain using traditional methods. 

However, what exactly is a rock garden? From a landscaping point of view, how do you go about building one? And what tools do you need to complete the job? Read on for answers to all these questions and more. 

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A rock garden, or ‘rockery’, is an area of land in your garden that uses an arrangement of rocks and alpine plants to create an attractive landscape focal point. Although not always the case, rock gardens tend to be used to take advantage of naturally sloping land or terraced areas. 

When built correctly, rock gardens are substantial domestic landscape structures that need very little ongoing maintenance. However, in order to create a rockery that lasts, you need to ensure you choose the right location, tools and materials to complete the job. Below we talk you through the entire process of building a rock garden, step by step.

First things first - before you start to create your new rock garden, it’s important to ensure you have all the tools and materials needed to carry out the work. Although this may depend on the size and scale of rockery you are planning on building, as a rule, we would recommend making sure you have the following tools and supplies before starting:

• Trowel
• Shovel
• Mechanical turf cutter (for large-scale rockeries)
• Tape measure
• Wheelbarrow (to move heavy items such as rocks and soil)
• Selection of rocks
• Topsoil, compost and mulch
• Your choice of alpine plant

Step 1: Pick a location

There are few restrictions when it comes to choosing a suitable location for a rock garden. They can be as small or large as you desire and can grace pretty much any area. However, if you are planning on including alpine plants as part of the feature, it is worth noting that an open area away from the shade of any trees or shrubs may be best. This is because these types of plants require a lot of natural sunlight to thrive. 

Additionally, it’s important to remember that although rockeries are versatile features and can be created on sloped, uneven and level ground alike, if you are planning on locating your rock garden on level ground, you may want to dig down slightly using a spade or turf cutter. This will create a dip with a small mound behind it that will give the feature more depth, making it more visible on your chosen landscape. 

Step 2: Choose your rocks

When it comes to selecting the right rocks and stones to use in your new feature, try to go for rocks that are naturally found in the local area. This will help to ensure they fit naturally into their surrounding landscape. It’s also important to choose a selection of different sized rocks and stones to avoid uniformity. Before buying expensive rocks from a garden centre or landscaper, it’s always worth paying a visit to any local quarries or reclamation yards in your area. Here you may find exactly what you need for a cheaper price.

Step 3: Prepare the site

Once you have selected your rocks and picked the perfect location for your new feature, it’s time to prepare the site. To do this, it’s a good idea to dig down between 10cm and 15cm, removing all turf and weeds as you go. For this a shovel and turf cutter can be used. In this newly created hole, lay a weed prevention membrane and then pile on a layer of coarse small stones, shingle or rubble 5cm deep.

Step 4: Place the rocks

Once the area has been prepared, you can now start to position your rocks. Begin by placing the largest rocks that will act as the main focal points of your new feature. These rocks should be placed at random to provide a natural look and should be bedded in using weed-free topsoil. 

Next, slightly smaller rocks should be placed around the large focal rocks. These smaller rocks can be used to wedge larger stones in position. As the process continues, keep adding rocks of various sizes using soil to bed them in and make sure you leave pockets of space for plants. 

Although not essential, you may also want to install a ‘retaining wall’ around the perimeter of your rock garden, made out of similar sized rocks or stones. This can disguise any overlapping areas of weed membrane and define the edges of the feature.

Step 5: Plant your shrubs and add mulch or compost

Finally, to complete your rock garden, simply add some alpine plants to inject colour into your new feature. According to the Royal Horticultural Society, the best alpine plants for rockeries include the pasque flower (Pulsatilla vulgaris), creeping thyme (Thymus praecox) and storksbill (Erodium). 

These types of plants thrive in soil that is nutrient rich and drains easily. We would recommend a half-and-half mix of multi-purpose compost and horticultural grit for planting. Once all plants have been added to your rockery, apply one final layer of gravel mulch at a depth of 5cm.

While it may take a few months for your rock garden to settle, if installed correctly it will soon become the low-maintenance yet striking garden focal point you wished for, effortlessly combining the natural ruggedness of the rocks with the injection of colour brought by your chosen alpine plants.