If you're planning on building a retaining wall on your property, you have to choose the right materials. While you might have your heart set on a particular style, it is important to consider other factors such as weight and slope.
Here are the four main materials and a discussion of their positives and drawbacks.
Stone is the most natural looking material. You can choose either fieldstone or cultured stone. Fieldstone is real stone that is harvested from excavation sites. It gets its name from the fact that farmers would dig up fields to plant crops and end up with large stones. These stones would then be used to build walls or even houses. Stone is either dry stacked or stacked with mortar. If it is dry stacked, the builder will often back fill the gaps with soil. These gaps can provide space for flowers and moss to grow.
Cultured stone is synthetic. It is made to look like real fieldstone, but it is often made of cement. It is not as strong as real stone, but it is much more affordable.
One drawback to stone, real or cultured, is that it is not suited for retaining walls that have to hold back a large hill. If you have a large hill in your backyard, and need a retaining wall for engineering purposes, not aesthetic purposes, then you should avoid stone. Stone cannot hold back the weight of a heavy load of soil.
Metal is used for areas where you need a lot of strength. It doesn't look nice, but don't worry, you can disguise it. The metal panels are installed like a fence. There are posts that are staggered at intervals and connect the main metal panels. Once the metal wall is installed, you can cover it with shrubs or even paint it.
Metal retaining walls are expensive, but they last a long time and require little upkeep. You don't have to worry about mortar cracking and needing to be fixed because there is no mortar, only rust proof screws and brackets.
If you need strength, but are not a fan of using metal, then you should look at concrete blocks. These are large blocks that are designed to be used for retaining walls. They are engineered to be stronger than regular cinder blocks. You might have seen them on construction sites, or even as part of a block wall at a large public park.
They are not as pretty as stone, but they don't require mortar. They are uniform in size and can be laid side by side with no noticeable gap.
If you are installing a retaining wall mainly for decorative purposes, then you should consider wood. Many people who have a sloping backyard don't need the strength of engineered concrete block or metal.
The only two woods that can be used are cedar or pressure treated wood. If you use cedar, you will need to have a plastic backer. While cedar is resistant to moisture, it is not completely waterproof. The plastic backer will keep the moisture from the soil from making contact with the wood.