The Best Rocks for Landscaping

Landscaping with rock is more than a vast desert of gray gravel, red lava rock or decorative white rock. When selecting rocks for the landscape, the best choices vary according to color, use and personal aesthetics.

Rocks range from pure white to dark greens, browns and grays shading nearly to black. When choosing rocks for the landscape, whether gravel or boulders, the colors should be compatible with the house and surrounding vista. For example, red lava rock may clash with a blue house and native granite boulders peeking through the foliage. In that scenario, a white-, gray- or blue-toned gravel may be a better choice. On the other hand, a mid-century modern home with red, brown or gold bricks on the facade settles nicely into a landscape that incorporates a warm brown gravel walk or red lava rock used as a mulch in the flower beds or around shrubs and trees.

Gravel is generally either man-made crushed rocks or naturally rounded, river-washed rocks. It is available in a variety of sizes and colors.

No. 10 screenings are 1/8 inch or smaller, much like a coarse sand. Screenings may be used alone for paths, although they tend to become muddy in wet weather. They are usually mixed with larger gravels and then compacted to make a solid, yet water permeable surface, such as a walk or patio.

Crushed gravel used in building gravel walks and patios is usually No. 57 size, which ranges from 3/4 to 1 inch. The rough edges of crushed gravel lock together when compacted firmly with a hand tamper or plate compacter. Smaller sizes, such as 3/8 minus, which incorporates 3/8 inch and smaller pieces of rock and dust, also make a firm, smooth walk. Crushed gravel is usually shades of gray, ranging from light to a medium bluish shade, depending on the vendor's sources.

The small, rounded pebbles, about the size of a pea, are known as pea gravel. No. 8 pea gravel is between 1/4 and 1/2 inch in size and may be found in a variety of colors, from grays to browns. Pea gravel tends to roll underfoot, making a soft path that may be difficult to navigate for mobility-impaired users. It is easily raked into the curving patterns found in Zen gardens.

Decorative gravels and pebbles range in size from No. 8 to No. 57. The rocks may be bright white, yellow, gold, pink, red, tan, brown, green, blue, purple, dark gray or black. Decorative rocks may have rough or smooth edges. Among decorative rocks are the bright white rocks and red and black lava rocks often used in landscaping.

Rocks range in size from No. 4 to No. 1, or 1 to 4 inches. Available in a wide variety of colors, rocks are used as borders, in dry streams and other decorative applications.

River rocks are rounded stones, worn smooth by the natural action of rivers. While river rocks are usually gray, they can be any color or combination of colors, depending on the type of stone.

Whether cut into flagstones or rectangular blocks, cut stones provide a relatively smooth surface for walks, patios, walls and other hardscape. The stones are often sandstone or other sedimentary rock, quartzite or slate. They are available in sand, tan, pinks, reds, browns, greens and blues. Fitted tightly together into a walk, square or rectangular cut stones are suited for wheelchair users.

Boulders may be granite, limestone, sandstone or other native rocks. The largest may weigh hundreds, if not thousands, of pounds. To provide a natural appearance, boulders should be partially buried in the soil. Whether anchoring a rock or desert garden, boulders add weight to the landscape.