Sometimes a garden calls or a different look – either a Mediterranean style, a patio or walkway that will not have a traditional dining table and chairs, or just a less formal look than concrete or stone. Details Landscape Art, design-build contractor in Petaluma, CA, has used decomposed granite on occasion in these situations.

Decomposed granite – or ‘DG ’ – is available in tan and gray colors, and compacts down to a very hard surface. In the Eastern part of the U.S. it is often called ‘hardpan’. It is actually crushed, pulverized rock. The main problem with DG in the past has been in the winter months. It gets soft and mushy when rained on, and homeowners and pets would track crumbs into the house on their shoes. In recent years, however, products have been developed called stabilizers, which, when added to the top layer of decomposed granite when it is installed, have bonded to the surface making it more solid.

The process of installation begins on a dry day with the excavation of the area, whether walkway or patio, to a depth of about four inches. Next, either benderboard or steel headers are installed on the perimeter or edges to contain the product. Two inches of base rock is then spread evenly, raked and then rolled with a drum roller. Next two inches of decomposed granite are added, leveled and then is rolled flat. At this point the stabilizer is applied evenly to the surface. It doesn’t need to penetrate deeply – a half inch is plenty. A Vibraplate machine is then used to compact the decomposed granite surface. A final application of stabilizer completes the project. The product should be allowed to dry thoroughly for several hours. It is probably a good idea to reapply the stabilizer every year or so, as it gets dirty, moldy if in the shade, and kicked around somewhat. We recommend scuffing up top inch or so of the decomposed granite, raking it smooth, applying a layer of stabilizer and rolling it flat with a drum roller.

Even with the stabilizer application, decomposed granite is not for everyone. If there is to be an outdoor table with legs, and chairs with legs, they will dig into the decomposed granite in spite of the stabilizer. The surface will be chopped up and uneven. Chairs are available, however, that have circular bases, that will dig less.

Decomposed granite is also useful as a dog area. When dogs are trained to do their business on a decomposed granite area, it is easily cleaned up, and relatively low maintenance, especially in the dry season months.

Costing quite a bit less than poured concrete surfaces such as flagstone, brick, stamped concrete and tile, decomposed granite hardscape yields an informal yet beautiful look, which is enhanced with low growing plantings that creep over and soften the edges. It is typically used in Mediterranean style garden, with olives, lavender, citrus and creeping thyme. It is seen throughout the south of France and Spain, used as patios, walkways, and even driveways.