Weekly Express-News Article

By Calvin R. Finch, PhD, SAWS Water Resources Director, and Horticulturist

Saturday, November 8, 2008

“Mortarless Garden Paths”

            Are you looking for a project that will enhance your landscape and not increase your water requirements?  Consider building a path out of flagstone or brick or decomposed granite without mortar.

            Leaving off the mortar means the project can be tackled with minimal equipment and it also means that your path is as good as mulch over your tree roots.  Water and gases can penetrate between the flagstone and bricks or through the decomposed granite.

            As preparation for your path project, scope out the options.  Books on paths and patios are good resource materials.  You can also visit Watersaver Lane at the San Antonio Botanical Garden where the six examples of xeriscape landscapes show several path options.

            Figure out where you want the path and mark with a hose laid out on the lawn.  When you settle on the location, width, and curves of the path, replace the hose with a paint marking on the lawn.

The marking paint is available as cans with a directed spray nozzle at home improvement stores.

            The sod should be dug out to six inches deep for best results.  Four inches of the dugout area should be filled with washed sand or a two inch layer of crushed caliche fill topped with two inches of sand.  By having the path at lawn level it is easier to mow the lawn. 

Tamp the fill material reduce future settling.  A block of wood attached to a 2 by 4 handle works or a tamper can be rented.  Foot traffic has also provided sufficient packing to provide a good base. 

            The sand provides a base into which the flagstone or other materials can be set.  Flagstone will only be roughly level, but brick and decomposed granite can be very level, especially if you edge the path.

            Straight paths can be bordered with treated 2 by 4s.  Curves can be accomplished with metal or plastic garden edging products.  The level can be placed from one border to the other on top of a straight 2 by 4.  At some point in your path, you may want a slope so water runs more easily off the path. 

            One advantage of building the path without mortar is that it can be changed if the final product does not suit you. 

            If there are tree roots in the path that prevent digging to a six inch depth, the fill depth can be reduced at that location.  In some cases, however, it is a better to cut a root out or at least cut a portion of its width off.  The path should be cushioned by at least two inches of sand.  Our trees are tolerant of some root pruning so the path digging will not be a problem for the trees.

            Flagstone makes an informal path.  Depending on your tastes you can have a stepping stone type path with considerable space in between the stones or a path with the stones closer together.  If the stones have more than one inch or two between them, the space can be filled with decomposed granite instead of washed sand. It produces a more firm surface than sand. 

Another way to fill the space between the flagstones is to plant Emerald zoysia grass or some other attractive traffic tolerant plant to provide a firm surface.  Strips of the zoysia grass can be cut from sod blocks and pleased in between the stone.  The grass will eventually fill all the gaps.   

            For a more formal look, go with the brick.  The bricks can be laid in patterns between 2 by 4s or other edging materials.  The brick without mortar is especially desirable for straight paths.

            Using decomposed granite for the whole path or combining stretches of the granite with stretches of brick or flagstone is attractive.

            Decomposed granite resembles sand, but is coarser.  It normally has a light brown color and forms a firm clean surface that fits very well into the landscape.  Decomposed granite is especially desirable as surface material for wide paths where tricycles, wagons, and wheel barrows will be utilizing the surface. 

            Washed sand, caliche fill decomposed granite and flagstone are available from the same retailers that provide compost or garden mixes.  They are also available from stone and rock supplies.  Bricks can be purchased from brick supplies listed in the yellow pages.  The treated wood, steel and rubber edging materials are available from some of the same suppliers and the home supply stores.