What to Use When Planting an Arborvitae on a Large Slope?

Treated Wood

• Create a terraced area by making a retaining wall using treated landscape timbers. Pressure-treated lumber can last 40 years without deterioration. Use landscaping timbers created for this purpose or old railroad ties. Wood is generally the most economical solution. The wall should be at least twice as wide as the mature width of the arborvitae. The height of the wall is based on the degree of the slope. Arborvitaes can grow as narrow as 4 feet or as wide as 15 feet, so be sure to plan accordingly.

Concrete Block Walls

• Sometimes referred to as keystone walls, these walls are made with uniform manufactured concrete blocks designed to interlock and create a wall relatively easily. There many style choices available and many that have the look of natural stone.

Fieldstone Walls

• Similar to block walls, fieldstone walls make excellent retaining walls. They can be built dry or with mortar. A sturdy stone wall requires a certain level of expertise to construct well, and it also needs the proper footings for stability. Fieldstone can range widely in price, depending on what is available locally.

Brick

• A brick wall usually requires a masonry professional, but you can do it yourself if you learn the techniques. Sometimes you can find old bricks inexpensively from building demolition sites. A brick wall creates a more formal appearance.

Stone Boulders

• A less expensive approach than retaining walls is to create an outcropping of stone boulders or large rocks to adjust the soil levels and create level planting areas. The boulders will help slow down water movement to prevent erosion. Use multiple sizes to create a natural look. The boulders must be set into the slope at least halfway to ensure that they do not roll down the slope.

Berm

• You can construct a soil berm no more than a foot high to prevent erosion in the planting area. Use plastic netting with staples to help hold the berm in place if needed. The berm can be planted with ground covers to help hold it in place as well. If the soil content is sandy and loose, a berm is not a good choice. Clay soil types make the best berms.