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RICHARD SHIELL: Landscaping more than just the plants

By The Bakersfield Californian

Landscaping is more than just plants. In fact some modern designs de-emphasize planting dramatically. Other aspects include earthwork (sculpting and mounding the soil), irrigation, lighting, all manner of outdoor amenities from water features to kennels to trash cans, lighting, open structures like gazebos, mist systems to cool them, walls and fences, and everything else on a site besides the building. All those improvements and amenities take materials, equipment, and labor that have up-front costs, and the potential to appreciably increase property values.

Saving money on landscape materials can cut project costs appreciably. Buying small lots with pretty packaging is generally not economical. For example, consider fertilizer: If 25-pounds of granular nutrients are applied annually on a property, we might choose between buying a single 50-pound bag to last two years, or buy five of the 5-pound bags annually. Say the 50-pound bag costs $20, and the 5-pound bags run $8 each. If anyone bothers to do the math, those smaller bags cost twice as much per pound in the long run.

The other issue is vendor; most home stores don't carry bulk fertilizer. Locations including Kern Turf, Gardener's Supply and Abate-a-Weed offer that kind of savings, as do many locally owned nurseries, including Bolles, Reimer's and White Forest. A big bag of 16-16-16 or 21-7-14 also reduces the number of trips taken, and the taxes paid.

Bulk materials are used in mixing concrete, laying flagstone paving, filling low spots, laying interlocking pavers on a sand base, and mulching over exposed soil. They are typically sold by volume, one cubic yard being the standard measure. A cubic yard is 27 cubic feet. For comparison, many brands of bagged mulch are labeled in quarts (so the number on the package looks more impressive), and one cubic yard equals 808 quarts. Pretty much one can assume that any landscape product sold by the quart isn't going to be any sort of deal.

The one advantage of bagged product is transportation; it's easier to carry into the backyard than a load of, say, bark chips piled in the driveway by a delivery truck. Then again, using a flat-ended shovel and wheelbarrow means there's no 3-mm-thick plastic waste to add to a landfill.

There are several locations in town for bulk materials. David Gieg of The Bulk Yard allowed me free rein of the facility to take pictures for this column. Tucked behind a couple of mini-malls on Rosedale Highway, located a block west of Calloway Drive, nobody would know without visiting that The Bulk Yard has a new building, a small fleet of vehicles, and the better part of an acre of organic and rock mulches. They are going on their third generation as a local business, and have a website, thebulkyard.com.

Another local bulk materials vendor is Buck's, located in Pumpkin Center, who also specializes in ponds and water features. The western branch of Bolles Nursery has bulk mulch as well.

Soil can't get sunburned, but the roots and organisms in the topsoil suffer when the surface bakes in our summer sun. A covering of mulch also helps conserve water, allowing the topsoil to retain moisture. Mulch should be applied in a thick enough layer to discourage weeds, and to provide some insulation for the soil.

Gravel mulch comes in many colors and sizes. Volcanic rock, termed "cinder" in the trade, comes in a range of reddish to brown hues. Smooth-sided river pebbles range from the size of mangoes to grapes, and are typically light grey (nearly black smooth stones imported from Mexico can be found in bags at a much higher price).

Rock mulch is mechanically graded by size as it passes over mesh gratings at the quarry, so for example 1-inch rock will be caught in a 1-inch gap while smaller pebbles pass through.

A mulch of big washed stones, used along a curved bed border a few feet wide, makes a dramatic accent in some southwestern gardens. They are an attractive feature of the Greenacres Fire Station (mentioned in this column back in June).

Rock mulch tends to mix with the underlying soil over time, as water and dust gradually move material, so landscape fabric is usually laid over the soil before mulching.

A landscape fabric is tough woven material that resists decomposition, typically for a decade or more, and has enough openings to allow air and water through, while somewhat restricting root penetration. Eventually enough dust, fallen leaves, and other materials will accumulate that a layer of soil will build up on top of the landscape fabric, so such an installation can be expected to last roughly seven to 10 years before weeds and possibly tree roots become an issue. Refurbishing the area requires the rock mulch be shoveled out and washed, and new landscape fabric be laid down before the rock is re-applied.

Unlike rock mulch, organic materials like wood and bark break down naturally when in contact with soil. My recommendation is not to lay fabric under organic mulches, but instead to add more of the same organic mulch as a top-dressing, and let the bottom part in contact with the soil just break down into humus and other useful soil materials.

David Gieg mentioned that the best-seller at The Bulk Yard is so-called "walk on bark," which is fir bark in a variety of sizes mixed up, some pieces up to 2 inches long. Fir bark is a renewable resource that breaks down slower than chipped wood, and has the advantage of no splinters. It comes in many sizes and grades from coarse to "humus," which is uncomposted fines. Redwood bark is sold finely shredded to a hair-like consistency, marketed as "gorilla hair" mulch. Bark mulches are extremely versatile and attractive, although the color gradually pales from sun exposure. Freshening them with about an inch of new material every two to four years is suggested.

Wood mulch varies from sawdust to hunks several inches long. Most colored bagged organic mulch is wood, not bark. An important thing to know about wood mulch is that it breaks down relatively fast (compared to other mulches), and that the soil bacteria that decompose it require nitrogen.

That means the topsoil underneath the wood mulch will become nitrogen-poor, and if fertilizer is applied then the mulch will break down faster.

In landscape projects wood mulch is usually reserved for tree plantings, to smother weeds. Wood mulches are typically applied thicker than bark mulch, about four to five inches deep, whereas bark is typically laid two to three inches deep.