Support your landscaping with a retaining wall
Residential landscaping in the South has evolved into an extension of the homeowners’ living space, designed with outdoor rooms and lifestyle areas. To build such spaces, the use of hardscaping has expanded to create a visual and structural foundation.
One of the most useful elements in landscaping is the low retaining wall. Landscape architect John Nespoli, owner of highly rated Germantown Landscape Company, includes them in his work in Memphis, Tenn., as well as throughout Shelby County and in Olive Branch, Miss. He likes walls for their aesthetic form as well as for their function. “A retaining wall can make a design more three-dimensional, creating level, graded areas,” he says. “I also use them out of necessity, when dealing with problems due to slope.”
However, Nespoli quickly points out that the most important feature of any retention wall is the drainage system behind it. Stormwater must be diverted away from the base of a wall to prevent it from destabilizing the structure. “It’s just as important as the wall itself,” he says. “You need a gravel bed with a perforated drainage pipe set in it with enough pitch for the pipe to drain.” In addition, the area where the stormwater runs out of the pipe also must be prepared with gravel and stones to disperse the water and prevent erosion.
A project’s budget parameters typically define the choice of materials for garden walls. Nespoli says that after the basic structural materials, the final costs are determined by how the wall is finished. “You can start with treated timbers or concrete and cinder blocks with stone facing and caps. Then you could go up to keystone blocks, sandstone and Arkansas fieldstone,” he says.
In the Blue Ridge mountains of western North Carolina, David VanWyck often faces an uphill battle in finding ways to create usable space in the landscapes. “I use retaining walls in my work out of necessity about as often as I include them for design purposes,” VanWyck says. “Whether we’re establishing grades that people can walk on or controlling erosion, walls help make space that people can use. Quite often we use walls to create terraces, which look great.”
His highly rated company, VanWyck LanDesign in Hendersonville, N.C., creates landscapes for mountain homes in a six-county region, including Henderson, Transylvania, Jackson, Macon, Buncombe and Polk counties. VanWyck says the preferred building material in this region is natural stone. “It looks older when it’s installed, a combination of clean and new with a strength that can stand the test of time.”
VanWyck builds retaining walls in the unusual style of dry stacking, without the use of concrete or mortar. This method of fitting and stacking natural stones together like puzzle pieces has been used in the British Isles and Europe for centuries. He backfills with gravel and installs drainage piping the same way he would for a conventional wall. Yet because of the way the stones are fitted together, they won’t shift over time or during winter freezes and spring thaws. “It makes a pretty wall,” VanWyck says. “It takes time, but it makes a stronger wall without gaps.”
Ellen Goff is a freelance horticulture writer and photographer who’s passionate about plants, water quality and the environment. She also stays busy with her own landscape and its inhabitants along the shores of Lake Wylie, S.C.