Rocks are used in many ways in landscaping. Rocks help set the landscaping theme and define the landscape as formal or casual. Rocks can make retaining walls, foot paths, sitting areas, define a pool area and make planters for both flowers and trees. Because the rocks are natural, no two are exactly the same. Each will have different patterns and graining.
Sandstone is durable and comes in buff, brown, green, yellow, gray, blue, black and pink. This is the one that is used mostly for retaining walls and raised planting areas for flowers and trees. Natural sandstone goes well with both modern and traditional landscaping themes. Sandstone is formed when sand is laid down and buried. Over time, it is compressed into stone. It can be quarried from river deltas, desert dunes or beaches.
Slate comes in black, green and red. It is one of the strongest of the landscaping stones, making it good for walkways. Its water resistance makes it a good choice for pool areas too. Slate is a finely grained sedimentary rock that is made up of clay or volcanic ash. Slate is very durable and can stand up to heat.
Marble comes in pink, white, black, yellow and brown. It is strong and has the capacity to absorb water. Marble is used to make pavers and retaining walls. Marble is metamorphosed limestone made up of almost pure calcite, a form of calcium.
Limestone has very little ability to absorb water. It is used mostly for retaining walls and comes in gray, black, white and buff. Limestone is a sedimentary rock made up of calcium carbonate, which in most cases comes from marine organisms. Pure limestone is white. Other colors are caused by impurities like clay, sand, organic remains, iron oxide and other materials.
River Bed Pebbles
River bed pebbles have smooth surfaces from having the river water wash over them continuously. They can measure 3/4 inch to 3 inches in diameter. Colors can be off-white, gray, pink, brown and green, and the shapes are round, oval or flat. The pebbles can be used in flower beds as decoration or mulch, in water features and in walkways.