The use of rock in the landscape has had a huge following for the past decade or so. There are several different ways to install flagstone depending on how it will be used and the look that we are trying to achieve.
When we make a flagstone walk or patio where we expect a lot of foot traffic, we build it so that the joints are close together. When a flagstone walk is built like this, we use over sized pieces with 2″ thickness and cut the stone where needed to minimize the gaps between each piece. This helps to make an even surface to walk on. This picture shows an example where we set the rock on decomposed granite and filled in the joints with the same. There are advantages to using decomposed granite as it allows for minor shifting, drainage and locks the flagstone in place.
Another method of installing flagstone is to plant between the rock. Often times this is accomplished with dwarf mondo grass. For this type of application, we leave a larger space between the flagstone, fill with soil and plant. I still prefer to use 2″ thick over sized pieces as it creates a surface that is easier to walk on. There will be more waste but the end result is better.
If we do not expect much foot traffic, then we often times will randomly place large pieces of flagstone. It provides a path for accessing an area but takes on a less important role for walking. This is often used to access a water faucet or a secluded utility area of the yard.