Garden Materials

This is an excerpt from the Book called “New Classic Gardens “ by Jill Billington. Continue reading to learn more about Garden Materials, thanks to the author.

Materials

Gardens that raise the spirits and delight the soul have spaces that are in balance and work to please, and it is particularly important in the formal garden that plants and hard materials should be compatible. In modern classic gardens this has meant retaining all that is good from the past-box hedging and stone flags, for example, have been comfortable associates for two thousand years-as well as welcoming in the new. Some of the familiar respected paving materials are now used in unexpected ways in the contemporary formal garden, while mixing old with new offers a variety of different textures.

Thoughtfully chosen material can emphasize a layout, whether it is reassuringly geometric or serenely asymmetrical. The geometrically planned layouts from the classical past of Europe and the Near East involved making axial routes, bisecting angles and laying out grid patterns. Such planning is still valid and may be enhanced by the wealth of new materials now available as well as the proven materials of the past. Oriental gardens had equally rigorous ‘rules’ taken from nature, without the conventions of straight lines and right angles. Modern gardens inspired by the Far East recognize this essentially simple, asymmetric style, ideally suited to modern architecture and chic minimalism, and are well placed to make the most of new flowing materials.

New Ways with Traditional Flooring

The paving materials used for centuries include large stone slabs and small setts, both quarried, and bricks made from local sand. In the past the cheaper option was to quarry locally rather than import superior materials, like travertine marble, over huge distances. While much of ancient Rome, for example, is paved with superb local black basalt, whose natural hexagonal structure sliced well to provide rough, strong paving, modern Jerusalem is built from beautiful local cream limestone that unites new buildings with the old city. Using native building materials for gardens ensured that they related well to the vernacular architecture as well as maintaining the spirit of place.

The same approach would be fine today if there were still plenty of affordable local materials from a sustainable source. But this ideal is now rarely an option, though attractive alternatives include floors made from mixed materials or from a simulated version of local stone. A more contemporary approach is to ignore the surroundings and allow the design of the site to be inward-looking, perhaps guided by the style the existing building or just the desires of the owners. The unity of this type of garden lies within and the materials chosen for its paving and boundaries may dictate its character. This is increasingly the case in the gardens of today and can give us a very free hand.

Stone

Natural quarried stone suits contemporary rigour just as well as the gardens of history. All natural stone is expensive but, if you have a small space, you may consider it worth investing in. Most stone darkens as it weathers, which adds richness and character to the garden. But the immaculate, absorbent limestones or new sandstones will need annual pressure cleaning if you wish to keep their light tone. In deep shade, moss and lichen may be a problem; this too can be resolved chemically but you must avoid run-off into planting beds.

Marble, basalt, granite, sandstone, limestone and slate offer a wide choice of textures and colours–no two flagstones will be the same shade. Choosing the right stone will depend upon the style of the garden as well as the budget. The close-textured, harder or finer stones suit an immaculate garden style best. So if the garden is formally chaste, the stone could be precisely cut granite or glossy Italian marble, its surface smooth and polished. A small courtyard of cool cream limestone or Cumbrian ‘green’ slate would be minimally elegant. Geometry is served equally well by hard French limestone in shades of yellow, rust and pink, or by granites, with feldspar pieces within the stone adding textural appeal. North American quartzite offers rough and close-textured non-slip surfaces, ideal around polls or pathways. In wetter climates all these hard stones would be too slippery, however; the roughened or textured surfaces of riven sandstone would be more appropriate.

The softer, grainy sandstones, for example York stone, are mellow in colour and suit a more relaxed formality. They are usually offered with a natural riven, non-slip finish in seven or eight differently sized rectangular slabs, to be laid in a traditional random jointing pattern. But sandstones are now also available in a smarter, non-riven ‘sawn’ finish. These look best if units of the same size are used. Rectangular units may be laid in a coursed pattern and square units in a grid. Both laying patterns are in keeping with the refined plainness of minimalism.

Some natural stones will be found in larger garden centres but for others you will need to contact a specialist stone supplier. Comparative costs may vary according to where you live but some of the larger chains, though having limited choice, do offer reasonable prices.

Setts and Bricks

Sometimes smaller-unit stone paving suits a space better than large units because it works well around curved edges. Such paving includes cobbles, rounded pebbles and square-or rectangular-cut granite or porphyry setts. The latter, though more expensive, lend themselves best to formally structured gardens. While all can be bought at larger garden centres, a wider choice is available from a stone merchant. Due to their high costs, granite setts are best laid professionally but for small areas you could lay cobbles or pebbles yourself on a concrete base. All create textured patterning at ground level and were usually laid in straight courses, concentric rings or ornamental fan shapes in modern gardens more elaborate patterns like zigzags or wave patterns are often deployed. A single course of mortared setts could be used to outline large concrete paving slabs, making a lattice pattern across the ground. Small units like bricks may also define grids.

Like stone, clay bricks will always have a role in the garden. While hand-made bricks suit romantic informal gardens best, they would also work in a modern asymmetrical garden outlined by thick timers or edged by large stones, or used in small groups as ‘stepping stones’ in a sea of gravel. Otherwise, choose factory-made frostproof brick pavers and lay them in a running bond that ends among plants or runs into fine gravel. This removes the need for ornamental edging, which was the old decorative approach. It is possible to add to the textural effect with lines of contrasting bricks, like hard-fired blue engineering bricks (Which can be more expensive than other colours) with brown, red and mottled ones, or lay them in lines of varying width.

Bricks can be laid on a base of hardcore and concrete or dry-laid on sand; the latter is less formal in its effect because the bricks are apt to sink slightly. To prevent all small units slipping into a soil bed at either end, it is advisable to build out a ‘haunch’ of concrete at the end of a row. If planning dwarf box hedging, you will be unable to plant close up to the paving. Frostproof factory bricks cost less than hand-made bricks and are cheaper to buy, but more costly to lay, than stone slabs.

Laying and Jointing

Traditional paving materials like stone work best when planned with defined straight edges; cutting paving to fit random curves or pointed corners always looks clumsy. Quality stone, usually cut as rectangles, should be laid neatly in parallel with the plan of the garden, even if this is the apparent space. Professional laying is recommended, preferably by a landscaper rather than a builder.

In the modern garden, stone is best laid in a coursed pattern in which length is emphasized and rectangular slabs are laid end to end in parallel. Each course, or line, of paving may be of a different width, with the jointing close-butted across the area-that is, with no gap between slabs-but the courses will be mortared lengthways. A formal structure does not mean that everything has to be edged. Unity is now more important, so edges may fade unobtrusively into the garden.

In many cultures grid-based designs have served the garden well and they are even more relevant today. Once seen as a decorative device, the grid is now used as a way of organizing the space. Small units like square clay tiles and brilliantly coloured glazed ceramic tiles are usually laid as a grid; be sure all are frost-hardened if your climate demands it-many terracotta tiles will not withstand frost.

Jointing should reinforce the dynamism of the garden’s layout. The linear pattern of coursed jointing emphasizes the order of a formal layout. If cut into square units, the flooring becomes more decorative, particularly when laid diagonally, making diamond patterns across the site. Mortared jointing may contrast with the colour of the stone but is usually more elegant tinted darker or to match the material. Purpose-made mortar dyes are readily available.

Mixing Materials

By mixing paving materials the effect at ground level can be considerably enhanced. This is not new: Zen paths used a mixture of unpredictable materials, making the visitor progress carefully, to appreciate the patterns underfoot. What is new is the choice of materials. In the formal context mixing materials should be done either for textural contrast or a contrast of colour, but not both because the effect would jar.

Traditional materials like brick can be given contemporary look with the addition of narrow bands of slate, and stone or concrete pavers look wonderful with slim strips of steel used as a jointing pattern. In one garden I laid Cumbrian green slate, in a coursed pattern and inserted slim strips of highly polished slate in a coursed pattern and inserted slim strips of highly polished slate between the non-slip, rough-surfaced pavers; these glossy strips dramatically intensified their matt colour. Sometimes flagstones can be softened by filling the jointing with plugs of tender, slow-growing Korean grass (Zoysia tenuifolia) or, in cool climates, dwarf thrift (Armeria caespitosa), with the bonus of small flowers.

Continuous, ‘flowing’ materials like concrete, which need expansion joints, may be laid in a large grid pattern by inserting small setts, tiles or bricks, or even narrow lengths of hardwood. Concrete can in fact have anything set into it and there is something very pleasing and restful about such organized schemes. Fired glazed ceramics mix well with stone or marble in a concrete foundation. Square glass bricks inserted into a pattern of matt grey or terracotta tiles have a double function when lights are placed below. And stone, concrete or railway timbers may provide a pattern of stepping stones in gravel.

Simulated Materials

Natural materials are no longer plentiful and their price has risen significantly. In the interest of economy and in order to spare the countryside, manufactures have developed new materials, such as concrete, that emulate natural ones as well as using reconstituted versions made from chips or powder of the original material. Reconstituted and simulated materials are often also cheaper to lay because they are of a constant thickness, which means that a large area can be laid at a time; provided there is a solid foundation, you should be able to lay these yourself.

The stone flags described on pages 16-17 can all be copied in concrete to make artificial stone but quality remains an all-important consideration. Casts are made to resemble the ‘parent’ flagstone in every way and the artificial slabs contain crushed stone within the concrete mix, ensuring the right textures and colours. When properly made they will weather as well as the real thing. Be sure to look for the better ones that offer many different sizes so that the duplicated slabs occur less often, and avoid those with a surface full of tell-tale air bubbles and chipped edges around the whole flagstone, which are entirely unconvincing. Good manufactures will choose old stones of character for the casts, perhaps even with chisel markings relating to how the original stones were quarried or used. Any colour should run evenly through the thickness of the stone so that wearing away will not change the look.

Concrete can also be used to simulate terracotta pavers for areas where frost is a problem. These may take time to mellow, and where the pavers are all exactly the same shape the result is very artificial. Some suppliers have produced pleasing effects by casting from real terracotta tiles but aiming to create the individual look produced by firing in which there will be scrape marks and a few punctured bubble holes. Some will be rough, some smooth and in shape they will look hand-made, which adds piquancy to strict formality. Sometimes a group of tiles is cast into a larger unit, reducing the cost; careful jointing can make them look effective and time will soften the newness to an extent. All can be laid in the modern pattern of coursed lines running in parallel, rather than the fussier chevron or basketweave patterns of the past.

Concrete ‘bricks’ are also available and all the reservations and virtues referred to above will apply. Some look almost genuine, with dragged surfaces and broody colouring, but you will need to beware of some horribly inauthentic colours. Clay bricks are rust-red, not the purple-red so often used in simulated brick or concrete pavers. Grey concrete ‘setts’ work well, particularly those with a pumice-stone surface, and there are some textured, cream-coloured setts that resemble the surface of travertine marble. They can be allowed to weather or may be pressure-cleaned once a year to maintain their pristine, pale appearance.

Some coarse concrete sets are of different sizes and are tumbled to break the manufacture perfection. They weather well and can be laid in geometric patterns if the area is large, such as a drive. To my mind there is nothing wrong with honest concrete slabs of an even grey or cream; they may have a stratified surface to make them safer and can look pleasantly regular for the modern formal garden.