Simmonds & Associates Articles

A Garden Set in Stone, Fine Gardening, October 2001

Pool Trends, Marin at Home Magazine, July 2007

 

A Garden Set in Stone, Fine Gardening, October 2001

Walls, paths, steps, and focal points made of rock unify this landscape and give it an established look.

by Warren Simmonds

Stone has been the building material of choice since man first stacked stones on top of each other to make a rudimentary shelter. It has a charm and naturalness unequalled by man-made materials. Used properly, stone brings people in touch with nature, creates a sense of timelessness, and becomes an integral part of a garden. So stone was the natural choice for a native-plant enthusiast's garden in northern California.

Our client purchased this property for the fabulous views of San Francisco and the bay, the high-ceilinged rooms that open to the view, and the stand of mature California live oaks (Quercus agrifolia) that inhabit the property. The structured, Modernist landscape installed around 1958 included concrete terraces linked by broad steps and wooden retaining walls painted black. It paid homage to the design of the house, but did little to relate the house to the oak woodland environment.

Our design called for a simplification of the existing landscape. There would be fewer terraces, and stone walls and flagstone paving would replace the retaining walls and broad paths. The stone terraces where the oaks could be enjoyed would be linked with curving flagstone steps that lead past boulder outcrops, a pond (photo 3, location), and through a sequence of different garden spaces.



Match your paving to your house's style

More than any other stone element, paving determines the character of your outdoor spaces. Since paving stone runs the gamut from irregular and rustic to very formal, it's best to match your paving with the style of your house. For example, if you own a Craftsman-style home, an irregular pattern of square and rectangular flagstones laid in sand best represents that period. A Georgian-style home might call for a more formal, rectilinear pattern, and a Mediterranean-style residence might call for a pattern of squares with inset diamonds.

In this garden, we not only wanted to use a natural material for the walls and pathways, but we searched for the stone that most closely resembled the native stone of the area. We settled on Shenandoah flagstone for the paving, Kennesaw dry-stack for the walls, and Sonoma fieldstone for the boulders. Though they come from different parts of the country, their character and color is similar, and they look like they belong in this garden.

Most importantly, the character of each expresses its purpose: The flagstone is smooth, broad and flat, and "says" walking surface; the boulders are rounded but sometimes craggy and speak directly to the natural environment of the Bay area; the Kennesaw ledge stone is blocky and angular in character, forms that suggest that they should be stacked in a wall.



Match steps with paving

As a rule of thumb, steps should match the paving to create flow between levels, as is the case in this project. The exception is where you want to change from a more formal paving to a less formal one. Steps can act as the transition, and the choice should be made as to which paving they should match, or whether they should be entirely different.

Stone steps should be set on a sound concrete base, as they were in this garden (photo 6 or 1, location), unless they are large slabs that can safely be set directly into the ground without fear of settling or movement. For safety, be sure to maintain a constant rise (step height) and run (step depth) throughout the flight of steps.

In this garden we curved the runs of steps between the different levels. This gives an organic flow to the garden, in harmony with the design goal of meandering through the Oak woodland. It also provides the opportunity to "find" out-of-the-way sitting areas that in a formal, rectilinear scheme would be obvious.

The steps are mortared to a concrete sub-slab for long-term stability and start at about 4 ½ to five feet wide, to invite people to explore the garden. Further away from the house, where the emphasis is on close communion with the plants, the path narrows and becomes stepping rocks set in the soil, only eighteen inches or so wide. This slows the visitor and encourages a closer look at the plants.



How a SPACE is used dictates what kind of stone to use

How a space is used also affects your choice of stone. Flat stones with mortared joints are preferable for entries, high traffic areas, and places with outdoor furniture. Irregular, dry-laid stones are ideal for garden paths and casual areas. In either case, make sure the stone is not too rough or uneven, which could present a tripping hazard, and not so smooth as to be slippery when wet.

Also consider color, porosity, and density. A light-colored stone may brighten a dark area, but can also create glare in a sunny area. Porous stones can absorb too much water, and may have to be sealed-especially on the shady side of a house where the water won't evaporate quickly, or in cold climates where the water could freeze and cause the stone to crack. A soft, thin stone should be mortared and laid on a concrete base to keep it from cracking.

In this client's garden, the terrace under the deck, adjacent to the pond, is one of the most used outdoor spaces. It made sense to set the flagstone on a concrete slab, with mortared joints. We quickly transitioned to flagstones laid on sand and with planted joints around the pond. Away from the house, further into the garden, the use areas become more rustic, and the flagstone is laid on sand, with irrigation and planting in the paving joints.



dry-laid walls look more rustic

In a natural setting, such as this garden, where a rustic aesthetic is desired, dry laid retaining walls are most appropriate. The stones are simply stacked without mortar, usually battered back at a slight angle into the hill to better resist gravity (photo 5, location). One of the beauties of dry laid walls is that they do not require a drainage system behind them, as water can weep through the joints between the stones. They can also flex and move in expansive soil conditions, without the cracking that can occur in mortared walls. Dry laid walls should not exceed about 3 feet in height; beyond that, they can become unstable.

If you need something taller, or are working in a more formal setting, stone walls can be built on concrete footings with mortar between the stones. Mortar joints can be kept thin, and recessed an inch or two from the face of the wall to give the appearance of a dry laid wall, where desired. Mortared stone walls may also have height limitations, require a rebar support system, or need drains and weep holes. Often, they require review by a structural engineer (particularly on the West Coast, where earthquake safety must be considered), so check with your local building inspector for guidelines.

Stone can also be veneered over concrete block or a masonry wall. This might be necessary where structural concerns require a very strong wall. When veneering a wall, pay particular attention to the corners, and try to avoid showing any thin edges of stone that will give a less-than-substantial feel to the wall.



hand-pick your boulders

We have used many different types of boulders in our various projects. We usually hand-select them for size and character. Almost always, the boulders that work best are those that appear to match the wall stone. Even if the same stone isn't available in boulder sizes, usually it is possible to find a close match in texture and color.

Exceptions can, and should, be made for boulders that are sculptural elements in a design. Examples from some of our designs are hexagonal volcanic plugs set vertically in the ground; rounded, river-washed granite "eggs" that are set into a lawn or around a fire pit; or that special boulder with the built-in birdbath that looks delightful by the porch or entry.

When used throughout a garden, whether as paths, steps, terraces, or as accents, stone can become a primary unifying element. While in this project we used three different types of stones, the variety was limited and carefully blended with each other in such a way that they are all seen as one with the surrounding environment.



Warren Simmonds is a landscape architect who specializes in creating outdoor environments rooted in nature. His firm, Simmonds & Associates, Inc., is located in San Anselmo, Calif.,

 

Updated April 22, 2008

 

Pool Trends, Marin at Home Magazine, July 2007

http://www.marinmagazine.com/Marin-Magazine/July-2007/Pool-Trends/

 

Updated April 22, 2008