Rocks are a very attractive addition to any landscape. They make the landscape appear more natural. Here are some ideas for rock placement.
You can use small stones for mulch. This is one of the choices for in-organic mulch, meaning, it doesn't break down like wood chips or leaves. Sizes are from 1/4 to 4 inches average size in bulk. Landscape rock is available in many colors and textures. Besides accentuating colors, landscape rock have several benefits. A fully covered area in the landscape will have more stable temperatures because the sun heats the rocks during the day. Then at night, rock stones slowly release the heat into the ground. Landscape rocks also stabilize ground surface moisture level, by slowing evaporation, thereby reducing your need to water. Use landscape rocks or gravel to replace lawn areas where ever possible.
Medium sized rock, say six to ten inches wide can be placed close together, but not clustered so that they are touching. Leave some space in between the stones.
To a landscape designer, stones are like paint to an artist. They add colours and textures to the landscape. Whether they be in a formal setting or more natural layout, landscape rocks are very versatile. Landscape rocks are available in many sizes, shapes, and materials. Many landscape supply centers even offer simulated landscape rocks made from fiberglass. Rock forms include natural stone, gravel in many different sizes and colours, landscape blocks, paver stone, as well as creative natural looking planter pots.
Aside from the visual appeal, rocks in the landscape have other advantages. For desert and arid climates, landscape gravel can be spread out to replace large areas of water consumptive grass. They also help moderate temperatures in the summer and winter. In the summer, they keep the ground cooler in the mornings, reducing ground evaporation. In the winter, the stones heat up in the day and keep the ground warmer through the night. The larger the rocks or the thicker the gravel, the more thermal mass protection you get.
Another advantage of landscape stones is that they reduce maintenance in the yard. Weed seed, that blows in from vacant lots, has difficulty germinating through a thick layer of gravel mulch; thus reducing wear and tear on your back as well as reducing the need for herbicides (weed killers).
The various types of landscape rocks have specific recommended applications in your landscape. Below are descriptions of best uses for different types of rock in the landscape. We start with the smallest types of rocks first, small gravel.
Most landscape rock is sold by weight in bulk. However, smaller stones can be found in plastic bags, and boulders can be sold individually. Buying in bulk usually gives you the best price as it is usually sold by the ton. But you can buy any fraction of a ton that you want, even just one bucket. It is usually can be bought at home garden centers, or dedicated rock retailers. You normally view samples of the various rocks available, then order the amount of weight that you think you will need to cover a given area in your landscape. You can bring your own pick up truck for loading at the rockery, or have the material delivered by dump truck. Delivery is typically $50-$100 per load. Some rockeries offer a discount if you order two different types of stones on one order. The dump truck will unload the aggregate in the street in front of your house. You'll need to cart the material to it's final spreading place with a wheel barrel.
Boulders can be used just about anywhere in the landscape, but here are a few general ideas for placing them in good locations. Plant shrubs around boulders that will mature at about the same size as the boulder. Shrubs that grow larger will overtake the boulder and make it disappear. If this is unavoidable, trim the bushes periodically. Set boulders partially buried so the look more natural in the landscape. Choose a boulder colour that complements that objects nearby. Make sure the boulder belongs and does not look out of place. If using multiple natural stone, make sure they are different sizes.
Landscaping with Caliche Boulders Much of the western United States has underground deposits of calcium carbonate. These deposits solidify and form large lime-stone boulders underground; typically under your property.
The boulders are random size. They range in size from that of a small potato to as large as a Volkswagen beetle. The larger ones are extremely hard to break up. Construction contractors hate them because it may add weeks to their schedule trying to remove them from the construction site.
The caliche boulders are typically white when first extracted, but oxidise to a light bronze colour after exposure to the atmosphere. They can be varnished to look like natural landscape stone. They are available for free in vacant lots around the city. For your landscape, they can be used to build walls and zone barriers.
You can also use flattened blocks of random shapes for your pathways. These are sometimes called paver blocks. Some are pre-fabricated, meaning coloured cement is poured in to a mould. The resulting block can either be square, rectangle, or polygonal. Natural slate blocks, called flagstone, are available in many earth-tone colours. They are usually mined from the mountains of the world.
Find out more about flagstone here, including a flagstone slideshow.

