Landscaping a steep grade presents a special challenge for homeowners. Erosion and water runoff are the two main problems that you must tackle. There are some techniques you can use to make your landscaped slope attractive and secure.
Terracing a slope will create flat, good areas for planting. It will also prevent erosion as well as poor water absorption. This is achieved by building retaining walls. A dry stacked stone retaining wall will work best for slopes less than three feet in height.
For slopes higher than three feet you will need to build several retaining walls. The mortar-less or dry stacked method will allow the stones to serve as an irrigation system. Water will seep through the cracks between the stones.
Select stones that have two flat sides. The heavier and larger the wall, the better it is. If you plan to build a straight wall you can use stakes and string to insure that the wall is level. Plot the placement of the wall with a hose or rope for a curve.
Dig a trench deep enough to almost bury the first row of stones. Place stones at a slightly back angle. This will make the wall more secure. The first row should be the largest stones but save some large ones for capstones.
Stacking the Stones
There are two ways to stack the stones. The first is placing the stones in somewhat uniform rows while matching the heights of the stones to the ones next to them. The other is a more natural stacking of the stones in a random pattern.
Either way careful stacking is important. Think of it as a puzzle. Try to fit each piece in as snugly as you can. This will create more stability in the wall. Backfill the wall with the soil left over from digging the trench and any stones too small for the actual wall.
Check for wobbling. Insert small flat stones into loose places to stabilize them. Another way to stabilize the wall is the use of deadman stones. These are long flat stones placed perpendicular to the wall. The outer edge should line up with the front of the wall. The back edge should extend into the soil behind it. The longer the deadmen stones the better.
Finally, you should complete the wall with capstones. Capstones are large flat stones equivalent to the first row in size and shape. They hold the stones under them in place and give the wall a finished look.
Railroad ties are an alternative to stone retaining walls. However, they require drainage pipes and possibly adhesive. If you don’t want to build a retaining wall you can still utilize large stones and boulders by placing them in the slope. They look best when arranged in a naturally occurring fashion.
Another option is to place a large stone border around the sloping area. A retaining wall is by far the best way to properly landscape a steep grade.
Plants and Mulch
Weeding on a slope may be difficult. A three inch deep layer of shredded mulch will help prevent weeds. Bark chunked mulch will slide down the slope, need replaced and require more maintenance. Gravel is discouraged because it to likes to slide down the slope.
Plants suitable for slopes should be drought resistant and dense. Junipers are sturdy, ground covering plants. They help control weed growth and erosion. They do well on sunny slopes. They are an excellent choice for a steep grade.
Pachysandra is another great choice for groundcover. They are a better choice for shady slopes. Creeping phlox will prevent erosion on slight slopes. It is not as effective as Juniper or Pachysandra. It produces beautiful flowers and does well in sunny areas.
Plants should be taller in the back and shorter in the front at the base of the slope. Plant them in masses to produce a dense cover. You can also use various shrubs, grasses and even a shade tree.
The correct landscaping of your yard will increase the value and beauty of your home. For an extremely difficult slope you may need to hire professionals who have experience with this type of landscaping to guarantee satisfactory results.
Photos by JMRosenfeld and Bernt Rostad, Creative Commons Attribution License