Three years ago, a chance visit to Utrecht University Botanic Gardens and a conversation with Connor Smith, head of the rock garden there, piqued my interest in rock gardens and their stylised cousin, the Czech crevice garden. As a result, I was determined to make a crevice garden when the time was right.
The work of Zdeněk Zvolánek, Joyce Carruthers and Josef Halda has shaped a global appreciation for crevice gardens, with notable examples at RHS Garden Wisley, Denver Botanic Gardens and the Jardin des Crevasses at Montreal Botanical Garden.
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At Utrecht, I saw the versatility of this approach, which can be scaled to fit any space, from pots and troughs to courtyards and larger expanses. And it’s not just stone that’s used – at Utrecht, reclaimed materials such as roofing tiles or broken concrete have been used since the 1980s, combining sustainability with creativity, way ahead of current trends.
Stone forges connection, linking the garden to its surroundings and providing a sense of belonging and permanence
Making a crevice garden
Crevice gardens are characterised by their careful arrangement of thin, upright slices of stone, set closely together but with enough space between them to create planting pockets.
This layout echoes the dynamism of natural rock formations. Larger pieces form the backbone and create rhythm and structure; smaller pieces are used to stabilise and give a sense of naturalistic balance, and are set with gaps for planting.
The outcrop slices are laid consistently and at the same angle, either vertically or slightly tilted. Typically, a third to half of each stone is firmly lodged in a base of coarse sand or crushed gravel for stability and drainage, so that the visible portions look as though they naturally emerge from the ground.
Choosing stone that has local provenance brings authenticity and reduces the carbon consequences of transportation
The base is permeable to ensure healthy root growth, and can be contoured to help lift parts of the crevice garden up or down. Planting mediums traditionally include a mix of grit, sand and loam, but some designers refer different mixes, such as pure sand for its water efficiency and low maintenance.
In this garden, a gravel mix is used both for the paths and for jointing the paving, using different grades of stone ranging from fine, dust-like particles to 10mm pieces, and with occasional larger stones accenting specific spots. This diversity in size creates a more natural, authentic look, mimicking the natural landscapes around us.
The beauty of stone
While crevice gardens are a specialised use of stone, the principles they embody – careful placement, attention to and observation of context, and integration with planting – apply broadly in all gardens. I can’t imagine a garden, whatever its size, location or setting, where the natural beauty of stone would be out of place. Done well, it just feels right.
The tone serves practical needs, offering durability and function that endures. It forges connection, linking the garden to its surroundings and providing a sense of belonging and permanence. It can be austere and elemental, speaking of the passage of time; it can be gentle and bucolic – flagstones softened by planting, or water trickling through stony streams crossed by monolithic slabs.
It also inspires – think of Laura Ellen Bacon’s ‘Natural Course’ at Chatsworth in Derbyshire, a mass of stone built using traditional dry-stone walling techniques that gives a sense of slow, gradual movement over the land; Andy Goldsworthy’s wriggling ‘Storm King Wall’ in New York’s Hudson Valley, built in part on the foundations of an old dairy farm wall; or Richard Long’s simple stone lines, evocative of place, time, distance and measurement. Their work shows how stone is not just a material, but a story and a connection between us and the landscape.
Right rock, right place
Choosing the right stone is crucial. Igneous stones such as granite and basalt are formed from cooled molten rock and are dense and durable, making them ideal for elements that need to be really robust, such as paths or water features. Their darker hues offer a more contemporary look. Metamorphic stone, such as slate, is created when existing rocks are transformed by heat and pressure. Slate’s layered structure and smooth, natural cleavage means it can be split into slim, flat pieces, and can be used for walling, paving, edging, water features and mulch, and depending on how it is laid and finished, it straddles both traditional and contemporary styles of garden.
Also lending itself to both traditional and contemporary styles is sedimentary stone, such as 8 sandstones and limestones, formed over millions of years as layers of sand, mud and organic matter are compressed into rock. Their natural patterns, textures and warm tones are charismatic and characterful, and they are generally easier than metamorphic and igneous stone to work and shape.
Within these types lies endless variation, and by observing the local geology of an area, and materials traditionally used in local buildings and landscapes, a garden feels far more rooted in its surroundings.
For example, in our projects in Scotland, we often reach for Caithness, with its durable and distinctive dark-grey, brown and blue tones. In the southeast, York stone and Portland are synonymous with London; York and its warm tones blends well into traditional and modern design. For our projects in the southwest, we have reached variously for the honeyed tones of Cotswold limestone for walls; the wonderful, fossilised qualities of Purbeck; the warmth of Herefordshire red; and the blue-grey tones of the lovely Blue Lias limestone for flagstones.
Choosing stone that has local provenance not only gives an authenticity and grounding to the space, but also reduces carbon consequences of transportation. What’s more, reclaimed stone, which is widely available, not only reduces environmental impact but also gives us materials that already have weathered qualities.
Finishing touches
The choice of stone finish is guided by the intended use, style and location. For paths and terraces, we prefer textured finishes to reduce slipperiness: riven, which splits along the stone’s natural grain, and is our go-to finish; flamed, where heat roughens the surface naturally; and bush-hammered, which we use occasionally to give a pitted texture. For a more modern aesthetic, sawn or honed finishes provide
a precise, clean look, though care is needed for grip. The texture of riven stone means that it’s hard to achieve a good finish when you are rounding off the edge for a step or a coping, so we specify sawn steps and copings to walls of the same stone to give continuity yet contrast.
Some 20 years ago, wide-eyed and inexperienced, I used York stone in a sawn finish for a path and terrace in my own garden. Like most sandstones, York stone is naturally porous. Its absorbency creates perfect conditions for algae to thrive in the shadier spots. It’s fine in summer, but in winter it’s slippery and needs cleaning with coarse sand, a stiff brush, some elbow grease and a few choice expletives.
With hindsight, I would opt for riven stone for better traction. On a practical note, it’s always worth investing in a decent-sized stone sample before ordering. Natural stone can vary greatly in colour, tone and veining, and a larger piece will help you better gauge how it integrates with the surroundings and complements other materials.
Creative ideas for a garden with rock and stone
A concept design by Harris Bugg Studio for a crevice garden in Scotland.
- Crazy paving has an undeservedly bad reputation thanks to its patchwork appearance and chunky joints. The trick is to ensure that the laying principles are intentional. Here, large and medium-sized stones form the core pathway, with smaller pieces weaving through and to the side. Joints are left open for plants to grow in.
- A stylised rock garden evokes the conditions of alpine landscapes, and is characterised by slices of rock set closely but not tightly together. The slices are firmly lodged by a third to half their depth below surface level into a foundational layer of contoured coarse sand.
- Squeeze stiles are wide enough for people to pass through, but not sheep and other stock. The cheek stone – the end stone positioned upright at the ends of the wall – tapers in, hence the name.
- Heights and sizes of stones vary to echo the natural dynamism of a rocky outcrop and provide varying microclimates. Slices are tilted in the same direction and visible edges face the same way, or have the same crust of cut rock exposed.
- Plants that thrive in well-drained conditions are planted in the pockets, into a grit and sand mix. They benefit from cool root spaces that hold some moisture but also drain in order to prevent waterlogging.
- Long stone block steps have large portions embedded in the wall, with the rest cantilevered as the exposed tread to ensure the wall provides an adequate counterweight. Always speak to a specialist waller and engineer when building steps.
- Feature boulders and rocks (of varying sizes for dramatic effect) add visual interest and natural focal points. They help define spaces, anchor planting, give rest to the eye and make the garden feel more connected to the wider landscape. They are also nice to perch on.
- Instead of being laid horizontally, edge-bedded walling is set vertically; sculptural and practical. This style is often seen in harbours to allow the tides to move through the stone with less resistance.
Case study for using rock and stone in garden design
Plunge pool with platform
It is not only the provenance of the stone that fascinates me, but also the traditional craft of working it, reflecting the culture, geology, history and anthropology of wherever we are making a garden.
We’re currently working on a project in the Inverness-shire countryside with Dualchas Architects. While they look to update the listed property, we’re working on the long-term development of the estate and careful, slow, gentle interventions to enhance access and enjoyment of an enchanting gorge stretching alongside the house.
Here, a burn tumbles steeply down in a series of spectacular waterfalls. The lowest of the falls,
reached by a woodland footpath, has a beautiful natural basin carved into the rock by the cascading water to create a magical, elemental plunge pool. When we started working on the project, it was impossible to get safely in – watery temptation, but out of reach.
Together with Lydia and Bert Noble of Noble Stonework, we worked with the existing character of the stone to create an inviting swimming platform and a walkway along to the tumbling falls: a pocket- sized, Scottish homage to Teresa Moller’s Punta Pite project – an arresting and creatively drawn trail through sea-cliff rock formations on the Chilean coast. With great skill and artistry, the masons created this gently crafted and stable, yet naturalistic and authentic intervention, with all the stone sourced hyperlocally from the site, to ensure that it knitted seamlessly into the setting.
A dip in the water here is exhilarating, with the earthiness of the surrounding woodland and the low, filtered light of the autumn sun.