How to create a rock garden

Landscaping can really be done at any time of the year as long as your soil is not frozen or soaked through. Planting and seeding can take place in the autumn or spring, depending on the plant.

Choosing the right spot for a rock garden

Rock gardens are generally used to make the most of a slope or embankment. If you only have flat ground, a rock garden might not be the best option for you, unless you are willing to form a little mound first.

South east- or south west-facing rock gardens will do best as they match the requirements of most rock garden plants. If you have a full south-facing garden, choose plants that are drought-resistant and can handle a lot of heat in the summer.  

You might also want to consider a mini rock garden. This can be a great option if you want to create a transitional space between a raised terrace and a lawn or a miniature garden on a balcony.

Choosing your stones

The type of stone you use will be a central part of the landscape so should be chosen with care.

You'll need around one cubic metre of stones for a rock garden measuring 10 m2.

You can use any type of natural stone. Sandstone or limestone are commonly used, but be sure to use just one type of stone as, unlike your rock garden plants, your stones should generally match in colour. That said, feel free to mix up the shapes and sizes of the stone.

To avoid your rock garden appearing artificial, it's a good idea to use local stone wherever possible.

Choosing your rock garden plants

Rock garden are generally filled with plants that cope well with dry, poor-quality soil.

Plant any flowering plants gradually throughout the year. Rock gardens often have a lot of flowers in springtime, but tend to look a little sparse over the summer.

In the spring, you can sow or plant annuals such as geraniums, marigolds and poppies, as well as annual grasses.

In the autumn, plant your bulbs (dwarf narcissus, muscari, tulips, crocus, etc.), perennials, (alyssum, pincushions, pasqueflower, houseleek, stonecrop, etc.) and biannuals.

Shrubs or dwarf trees come in a variety of shapes and colours and can be used to line the back of your rock garden or the highest part of the garden. You may also want to add some conifers to the mix (juniper, pine, etc.) alongside some evergreen or deciduous trees (such as spindle or cotoneaster trees). This will add a splash of colour to your garden over the winter. If arranged with care, they'll also provide a sense of height and volume to your rock bed.

Working the soil

The soil should be turned over a fair bit in preparation. If you have poor-quality soil, add some top soil. If the clay content is too high, balance out the soil with some coarse sand and manure, as you will need good drainage. It will be difficult to improve the quality of your soil at a later date, so it's best to start now.

You don't need a particularly deep layer of soil as most rock garden plants are happy in relatively shallow earth.

Laying your stones

Be sure to place any large stones in a way that looks natural: do not place any stones standing up and make sure your stones aren't too neatly lined up while keeping the overall surface as flat as possible.

Ensure your stones stay in place by burying them down about a third of the way. You can then spread out smaller pebbles or lay a bed of gravel.

In order to prevent soil erosion on steep inclines, set up banks, using large stones to create a little stairway.

Start by positioning your largest stones at the bottom of the slope. You can then spread out smaller stones and fill the gaps between them with soil if necessary.

A small supporting wall at the base of the rock garden can be handy for marking out a passageway.

Planting in a rock garden

Once your soil is in place,  wait a few weeks for the new soil to stabilise itself. Remove any weeds that might have cropped up and start planting.

Before placing your plants in the ground, position the pots in the rock garden to get an idea of the finished look.

You can plant vegetation quite densely to begin with to ensure the soil is well covered. Remember that you can always divide your plants later on.

Once everything is in place, you can tend to the particular needs of each plant: for example, add a little more gravel where you have planted bulbs to avoid excessive moisture or a handful of peat for any plants that don't like acidic soil, and so on.

Mulching with pebbles or coloured gravel is a great idea in a rock garden. In addition to providing a decorative touch, this will help the garden retain moisture when there isn't much rain, prevent soil run-off on steep slopes, and limit the amount of weed growth.

You can also use pine needles as mulch. Weed control fabric should be avoided at all costs as it does not look natural.  

Don't forget to water your rock garden regularly (but not excessively) during its first year.