Although this article was written with Southern California in mind, the concepts are universal and can help people design landscapes in just about any garden anywhere.
One of the most powerful natural decorative effects in a landscape design is the placement of stone, rocks and boulders. Rock varies as you travel through Southern California. Even locally you can see the wide mixture of stone that has been pushed to the surface by the contorting jolts of earth movements in our hills and mountains. There are sandstone rocks in reds, beiges, yellows and whites as well as multicolored granites. You can find wind and water rounded rocks and boulders and sharp-edged splintered rocks. Some areas boast iron in the stone formations making them orange and others are laced with copper that turns rock green. Mica and quartz can make stone glitter. There are rocks and boulders that will go with just about any kind of landscape you may want to design on your property.
Rocks are perfect to enhance a Southwest landscape theme, to set off the interesting shapes of a cactus and succulent garden or to offer natural seating in a wild or native landscape design. Add a boulder to highlight an ornamental grass garden or use scatterings of rocks to trace out a dry riverbed. Single stones can be the focus of an Asian or Zen garden or they can be carefully placed to be used as furniture or to set off a shapely tree. Design with rocks and boulders into almost any theme to add accents and character. They can also be used to create spacial effects and perspective illusions.
You can buy rocks and boulders, priced by the pound or you can collect your own from your own property or from open, undeveloped land or dry rivers. Do not take rocks or stones from parks or other California public areas: it is against the law. If your yard has an unblocked view of surrounding land, you might want to choose the same kind of rocks that will blend with your local, natural stone. Using a material that continues outside your boundaries will help your garden to look like it flows beyond your property line
Avoid equally spaced rocks forming a pattern unless you want to create a formal, contemporary or minimalist design. Often landscapers with no design sense will line up stones or set them in neat, equidistant spaces. Nature would never do that and these overly calculated rock settings look silly in anything but an intentionally contrived – and carefully, artistically designed –overall landscape design.
Rock and stone can be integrated in walls and into the surface of concrete. Pebble finishes can be used for textural effects and designs can be drawn into different areas of colored stone. Big boulders make powerful statements. They can guard an entry or tower over a natural-looking dry river bed, stream or pond. Rocks are heavy so expect to need power equipment to move them unless you stick to sizes less than 18 x 18x 18 inches. Medium rocks can be moved with a crow bar or lifted with the help of several strong backs. Be very careful when moving rocks. They are very dense and weigh more than they appear. Always lift with your legs and don’t try to move something that could cause injury.
Look around at some examples of the landscape design with stone and rocks by checking out garden magazines or the Internet. Visit parks and public gardens. Do you want to create your own stand of jutting rocks? Do you like the squat, rounded rock forms that pile into mounds? Are stacked walls or flat flagstone areas more to your taste? Decide on the kind of stone, rock or boulder you want and blend it into your own garden. Build with rocks and stone that will complement your garden style, the area you are living and even the design of your house.
Adding stone, rock and boulders not only creates interest in the design, but it can help you build areas of drainage and permeable paving that will help with excess rain run-off during the winter wet season. Gravel offers water-saving, non-growing surfaces for practical use, play or design. Use it to fill in hard-to-plant areas so they look great in hot or cold weather and smother invading weeds in spring. Stone is a natural product that can be used to advantage in your landscape design. It can even function as a top-dressing or a layer of mulch. Just remember that dark colors absorb heat so they can get hot in summer sun for delicate feet and plant life.
Natural rock comes in all sizes, shapes and a surprisingly wide range of colors. Use it in your garden for ease of care and beauty. It can become one of your most important and stable design elements.