Articles by Jim Gainan

As published in the Billings Gazette

Gardening Today: Installing Landscape Edging

Installing Landscape Edging
In order to create a low-maintenance landscape, it is essential to include lawn edging, weed barrier fabric, and a mulch in your planning. The use of these materials can add the finishing touch to your landscape as well as making maintenance chores such as watering, weeding, and hand-edging of grass less time-consuming.


The purpose of landscape edging is to provide a barrier between the lawn and the planting bed. Many different types and grades are available. The most commonly used edging materials are vinyl, steel, or aluminum. These edgings are usually sold in lengths or 'sticks' of 16 to 20 feet. Their suitability as landscape edging comes from the fact that they are pliable enough to be installed in a curving line yet stiff enough to be laid in an un-wavering straight line.

To install edging, begin by placing a garden hose or string line along the curve or line that you want to edge. Another trick is to 'paint' the edge with spray paint. Dig a trench about 4 inches deep, using a flat shovel or a trenching shovel. If the ground is very hard, you may want to soak the ground prior to installation. Keep in mind that you want the top of the edging to be level with the existing sod.

Other materials, such as stone, brick, wood, or concrete are also suitable as edging. Rock flagstone or brick should be grouted together in order to provide a continuous barrier between the lawn and the shrub bed. If grout is not used, you may tuck the edge of your weed barrier fabric beneath the stones or brick.

If wood edging is used, realize that you will not be able to make curving lines. Landscape timbers or railroad ties make a good 'edge' as well as a good mowing strip. As with other types of edging, make sure that the top of the timber or tie is flush with the level of the sod.

 Weed Barriers
Landscape fabrics provide an effective control of weeds in landscape beds. The fabrics, which may be woven or spun, allow an exchange of air and water between the atmosphere and the soil-a definite advantage over black plastic week barriers formerly used. Less moisture is lost to evaporation, allowing more moisture to be retained in the soil.

Weed mat can be installed in two different ways. In un-planned shrub beds, lay the fabric upon the soil, cut holes in the fabric where you plan to plant each shrub, excavate the soil in the holes, and then plant the shrubs.

Another method, which applies when planting any shrubs that are under 3 feet tall, is to lay the fabric over the top of the shrubs, cut an 'x' in the fabric at each shrub, and pull the fabric over the plant to the ground.

Weed mat pins, or companion pins, are often helpful in securing the fabric to the ground, especially at the edges of the bed, near the edging.


A 'mulch' is any material that is applied over the soil to suppress weeds, modify moisture and soil temperature, reduce erosion, or add organic matter to the soil.

An important consideration to make when designing your landscape is the selection of the type of mulch to be used. The mulch you choose should complement the color or style of your home.

There are many different mulching materials available but they usually fall into one of two types-rock or organic (bark).


Rock Mulches
The advantages of rock mulches are that they are long-lasting and heavy, which helps to hold down the landscape fabric upon which it is placed. A weed barrier should always be used under a rock mulch.

Rock mulches are available in several different colors, depending on the type of rock. Some of the choices available locally include:

  • Scoria-pink-orange pea-gravel or chunk size
  • Lava (volcanic) rock-gold, burgundy red, or mahogany brown available in 3/4" or 2" chunks
  • Dolomite-mauve-burgundy with shiny white crystals
  • Marble chips-sparkling-white chunks
  • Pea-gravel-dark gray 1/4" to 1 1/2" diameter
  • Washed gravel-rounded, smooth, gray stones available in 1/4" to 1 1/2" diameter
  • Cobblestone-light gray 3 to 5" boulders
  • In order to determine how much rock you will need, multiply the area to be covered (length x width) times the depth of rock desired.

Most mulches are applied at a 2 to 3 inch depth. Two inches equals .16 cu. foot. Three inches is .25 cu. foot. Area (square feet) x Depth (in feet) = Volume (cubic feet). Since rock is often sold by the 'yard', you must convert cubic feet to cubic yards by dividing the cubic feet by 27. Cubic feet รท 27 = Cubic Yards

 Organic Mulches
Organic materials, such as bark chips, are attractive, natural-looking mulches that blend in well with most landscapes. The most commonly available organic mulches are different forms of bark-ground bark, shredded bark, or chipped bark. When using bark as a mulch in a shrub bed, a weed barrier should be installed first. Since bark mulches will decompose and lose their color, plan to replenish the bark every other year or so.

Perennial flowers are best planted in beds which feature an organic mulch, which may be ground or shredded bark, leaves, grass clippings, or pine needles. Keep in mind that any of these organic mulches will rob your plant's roots of nitrogen as they decompose unless you add a high nitrogen fertilizer (lawn fertilizer) to the mulch occasionally.

One of the best mulches for a perennial flower bed is a pre-composted bark product called 'Soil Pep Soil Conditioner', which has already been decomposed and does not use nitrogen. Besides adding to the organic content of the soil, 'Soil Pep' (or other bagged compost products) cool the root area, loosen the soil, and modify the pH of our basically alkaline soil.

Bark mulches are usually sold in 3 cubic foot bags. To determine how many bags you need, multiply the Area X Depth (.16 or .25) to obtain a total Volume (cubic feet). Divide the total cubic feet by 3 to determine the number of bags needed.