How to Build Rockery Gardens

Overview

Rockeries are a popular form of garden design in Britain, combining alpine plants and rocks to create a naturalistic haven in your garden. Building a rockery requires careful planning, design and plant selection to achieve harmony between the harshness of the conditions and the softness of plants. By the end of this step by step guide, you'll be able to build your rockery into a stunning focal point for your outdoor space. Our goal is to keep it as focused on the construction aspect as possible while making it easy to follow.

In order to do that, we have also put together a companion article called: Creating rock gardens with plants. Its aim is to provide you with comprehensive information on how to plan and create a rockery, from designing its layout and a specialist environment for rockery plants, to choosing your feature stones and rock plants. 

So that you don't have to wade through any unnecessary information, each section has a TLDR of the main points covered so you can easily scan to find the information you need at any time. Also, there are quick links to help you to navigate easily to any of the following sections:

With our comprehensive step-by-step guide, we will make sure that you successfully build a long-lasting and stunning rock garden without ending up hitting the rocks.

Also, don't miss out on our 'Pebble Picker' tool in the sidebar or menu. With it you can choose and browse every decorative aggregate by colour and type with ease.

What is a Garden Rockery?

A garden rockery is a type of rock garden that includes rocks, gravel, occasional oddities like statues, and alpine plants. Rockeries are designed to mimic natural rocky landscapes, providing a unique and visually appealing feature in a garden setting.

Rockeries are useful for beautifying slopes or areas with poor soil quality as they can improve drainage and create a specialist environment for alpine and other rockery plants. They come in different sizes and complexities, from slate rockeries and small gardens to larger designs featuring gravel paths in gardens with various rock types and plant species. Building a rock garden is more about careful planning and catering for the plants' specific needs than it is a hard landscaping task that requires previous experience.

Primer on Designing a Rockery Garden

In a nutshell, before you make your rockery, you need to plan where it should go. To do this, you need to consider the size, shape, available sunlight and drainage. Then you can select the rocks and stones, plants and other accessories that you want to decorate the space.

Choosing a Place for Your Rock Garden

When selecting a location, choose an area that receives plenty of sunlight, as most rock garden plants are sun-loving. Ensure that the soil is well-draining to prevent water from pooling and potentially causing damage to your plants. Where there is a lack of sun, shade-loving plants range from elegant ferns and vibrant impatiens to exotic caladiums and hostas. We have a list of shade-loving plants in our companion article about creating rock gardens with plants.

Additionally, consider the accessibility for maintenance. Ideally, the rock garden should be visible and easily accessible from different angles. Finally, take into account any existing structures or trees that may impact the growth of your plants.

Which Types of Rocks to Use

When it comes to choosing rocks for your rockery garden, there are several options to consider. Natural stones, such as limestone, sandstone, and granite, are popular choices due to their durability and natural beauty. They come in a variety of sizes, shapes, and colours, allowing you to create a unique and visually appealing garden.

Colour

Decorative aggregates like gravel, pebbles and cobbles are great for adding texture and color to your rockery. Our encyclopaedia of decorative aggregates provides a comprehensive list of stones and gravels in the UK, with each entry offering detailed information and links to helpful guides and DIY projects. It's linked to our colour-matching tool in the sidebar. If you haven't clicked on it yet, feel free to give it a try! 

What Plants are Suitable for a Rockery?

Rockery plants are resilient and come in a variety of shapes, sizes and bloom colours, providing year-round beauty. Also, because they are well-adapted to poor, well-drained soils, they are a smart choice for gardeners seeking low-maintenance options. A variety of plants are suitable for a rockery garden, but it's important to choose species that can grow in the unique conditions of your garden. Some examples of suitable rockery plants include:

Then there are the alpine species, which are particularly well-suited for rockeries because they have evolved over millions of years in rocky and mountainous environments. Remember, when selecting your plants, consider the sunlight, their tolerance for drought and the soil conditions to ensure their suitability for your rockery garden.

Next up, we get down to business, beginning with a list of tools and other materials essential to the construction of your rockery garden.

List of Materials and Tools

In this section, we cover the remaining essential materials required to build a rockery and follow that up with a list of the tools required for your project.

Materials List

Alongside your rocks and plants, you will also require some other materials. Gravel or stone chippings are useful as a top layer to add to colour and texture while improving drainage. Depending on your existing soil, you may need to amend it with compost, topsoil and sand to improve drainage and fertility. Adding some compost for enriching the soil to support healthy plant growth is also something to have on hand.

Also, nothing beats the addition of a weed membrane in order to minimise upkeep and improve drainage and stability. When installing, the membrane must be secured with pegs or spikes.

Lastly, edging is an optional and nice way to create a hard border for the containment of your rockery. With prefabricated edging made from materials such as metal or wood, rubber or plastic alongside traditional items like bricks, stone, or logs, the options are almost endless. These issues are covered in our article: How to Make Edging For a Garden.

List of Tools

The following is a list of tools which are mostly essential to a smooth operation, the majority of which you should have in your garden shed or easily be borrowed.

How to Build a Rockery in 9 Steps

Building a rockery garden is an easy-level DIY project, which can be very rewarding and enjoyable. Here is a step-by-step guide on how to build a rockery in 9 simple steps. We begin with the planning stage.

1. Plan Your Rockery

Before starting your rockery garden project, it's essential to plan and design it carefully. Consider the size, shape, and layout of your rockery to ensure it fits harmoniously in your garden. Consider the natural contours of the landscape and any existing features that can be incorporated into your design, such as trees, walls or a water course. Take note of the amount of sunlight the area receives and record your measurements for accuracy.

Plan for a variety of plant species and create different planting zones according to their light and moisture requirements. Sketch out a rough design, called a skeleton plan, and determine the type and number of rocks and plants you'll be adding and where. Planning your rockery garden on paper helps you to visualise the final result and make the construction process smoother.

2. Mark Out the Area

Now that you have everything you need, it's time to begin building your rockery garden. Mark out the area where you plan to build, using stakes and string to outline the shape of the area. When marking out the area, keep in mind the desired height and depth of your rockery.

3. Prepare the Space

Preparing the space is an essential step in building a rockery garden. Start by digging out the area, removing any roots, existing vegetation or weeds as you go. Clear the ground of debris, and with a rake, level it out as much as possible. It is also important to maximise the potential drainage, especially if the area is prone to water accumulation.

In most cases, it's best to improve drainage by adding a 3-10cm (1 - 4 inches) layer of gravel or rubble. The more clay or poor-draining your soil, the thicker your base should be. This will require you to dig 3-10cm below the depth you need to excavate for your topsoil mix, so factor that into to your planning. If you plan to install any lighting or irrigation systems, now is the time to lay the necessary groundwork.

4. Add Drainage Gravel

At this step, it is time to add a layer of gravel or rubble to prevent water from pooling around the roots of your plants, which can lead to root rot and other issues. Start by spreading a layer of gravel evenly across the bottom of the area. The gravel should be 3-10cm (1-4 inches) deep. This will also help to stabilise the rocks, creating a secure foundation for your rockery garden. Find out more in what is sub base?

5. Lay Garden Weed Membrane

To prevent weeds, it is advisable to lay a landscaping fabric as a garden weed membrane. Preferably a non-woven type, it blocks sunlight and also prevents weed seeds from germinating. Once your base is down, simply roll out the weed membrane over the entire surface of your rockery garden.

Cut holes for your plants and trim the edges, leaving a few inches of excess fabric to be tucked under the surrounding soil. Secure the membrane with landscape pins or staples, aiming for a flat and tightly stretched finish across the area. This will also aid in drainage and keep the top layer of soil and rocks well separated from the base.

6. Placing Your Stones

Once you have prepared the space and laid the weed membrane, it's time to start placing your stones according to your skeleton plan. Starting with the largest boulders, arrange your rocks in a way that creates a balanced and natural-looking landscape, considering the size and shape of each stone.

Ensure that they are securely embedded in the soil or gravel, using smaller rocks to fill in gaps and to create interesting formations, such as crevices. It's good to vary the height and angle of the stones for adding dimension to your rock garden. Take your time and experiment with different arrangements until you are satisfied with the overall look. We also have some more tips for Planting a Rock Garden.

7. Add Smaller Rockery Stones

It's time to add the rest of your smaller rockery stones and gravels. These help to create planting pockets and fill in the gaps between the larger rocks which produces a more natural and cohesive look. Scatter the smaller stones throughout the rockery, making sure to distribute them evenly. This will also provide stability for the larger rocks to prevent them from shifting.

8. Add Compost Mix

Start by filling the gaps between the small rocks with a good compost mix. Alpine plants prefer a mix that is free-draining and has a neutral pH. To create the ideal combination, mix equal quantities of coarse sand and general-purpose compost. Spread the compost evenly throughout, gently tamping it down to remove any air pockets.

9. Position Your Plants

You're nearly there, congratulations! Now it's time to position your plants. Place taller plants towards the back of the rockery and shorter plants towards the front to create depth. Ensure that each plant is positioned securely, with its roots covered by the compost mix but not buried too deeply. Take your time and experiment with different arrangements before committing to the final planting.

Summary

This guide has walked you through the essential steps of planning, selecting and establishing your rock garden, highlighting the importance of considering sunlight, good drainage and the right mix of rocks and plant species to suit your garden's special conditions. With some careful planning, selection and understanding of your garden's microenvironment, you can use the right plants to create a long-lasting and dramatic rock garden that will add to the value of your home.

In conclusion, building a rock garden with plants is a rewarding task that does not require previous experience in order to get a satisfactory and pleasing result. By combining the rugged beauty of rocks with the vibrant colours and life of plants, you can create a feature that not only adds beauty to your outdoor space but is also low-maintenance and DIY-friendly.

FAQs

How do you make a simple rockery?

When creating a simple rockery, start by choosing a suitable location in your garden. Clear the area of any weeds and debris, then lay down a piece of landscape fabric to prevent weeds from growing through. Add a layer of gravel, rubble or broken bricks to create a base layer for the rockery. On top of this, add a layer of grit or gravel to help with drainage.

Next, mix together horticultural grit, topsoil, and leaf mould to create a weed-free topsoil mixture. Use this mixture to build up the shape of the rockery, creating a small mound with large rocks to add structure. Fill the planting pockets with a range of plants, such as shrubs or small stones, to create an attractive and low maintenance rockery.

Finally, sprinkle small decorative aggregates or coir onto the rockery to finish off the design. Keep in mind that the best time to build a rockery is generally spring or early autumn if you plan to add plants at the same time.

What compost is best for rockeries?

A well-draining compost mixture is best for rockeries, as these plants typically prefer sandy or rocky soils. A mixture of equal parts sand, gravel and compost is good for providing the right balance of drainage and nutrients for plants. Additionally, using a mix with added perlite or vermiculite can aid in improving aeration and drainage. If you are purchasing one, choosing a compost that is low in organic material and high in mineral content is important to mimic the natural conditions of a rocky environment. 

What soil is best for rockery plants?

The best soil for rockery plants is a well-draining, sandy or gravelly soil mix that is low in organic matter. This type of soil will mimic the rocky, well-draining conditions that rockery plants naturally thrive in. Adding some coarse sand or small pebbles to the soil mix can further improve drainage and create a suitable environment for rockery plants to grow. Amend the soil with some mineral grit or limestone chippings to provide the plants with the necessary nutrients and pH levels. Avoid using heavy, clay-rich soils as they can retain too much moisture and cause root rot in rockery plants. 

How to build a rockery against a fence?

Constructing a rockery next to a fence can transform the look of your garden while making use of any unused space. Here's how to do it:

Select a Spot: Choose a fence that receives enough sunlight for your chosen plants to grow.

Area Preparation: Remove any debris or weeds from the base of the fence and level the ground.

Foundation: Cover the cleared area with a protective membrane to prevent weeds from growing through the rocks.

Rock Placement: Begin by positioning larger rocks at the base of the fence, gradually building up and staggering their placement.

Arrange plants: Intersperse suitable plants between the rocks, ensuring they have enough room to grow.

Add more rocks and plants: Continue building up the rockery by adding smaller rocks and additional plants as desired.

Water In: Give the area a good water and care for the plants according to their specific requirements.