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Ask a Landscape Designer: Is Gravel Good in the Garden?

Gravel in gardenQuestion: Could you find a landscaper to comment on pros/cons of pea gravel in a residential setting? I’m entranced with the look, and permeable hardscape is important to me.

However, when I research on the Internet, I find most postings by homeowners are negative: It does not stay put if there are children or dogs in the household, neighborhood cats use it as litterbox, ants build mega cities in it, it’s not a realistic choice if children run barefoot in the yard, a wheelbarrow pushed down the path creates ruts and sends pebbles into the flower beds.

I’ve also read that 2 inches is not sufficient and that 6 inches is needed and that the gravel should be mixed with aggregate to stabilize it better.

Answer: From Pamela Berstler, landscape designer of Flower to the People in Los Angeles:

We LOVE gravel as a mulch in the garden, and most people in the Mediterranean would agree with that assessment. It reflects heat, but protects roots, and it maintains moisture, reducing the need for irrigation, and does not decompose and require replacement.

The wide variety of local colored stone can really enhance a natural landscape installation, but we try to stay away from exotic or excessively processed material, as it is not a sustainable solution.

Gravel mulch and pathways require different treatments. In the garden beds, as mulch, 2 inches is pretty much the maximum required (not 6 inches). You actually want to use less rather than more, as the deeper the gravel application, the more difficult to keep it away from the base of plants, keep ruts out and keep it from spilling everywhere. When the application is thin and slightly compacted, it works beautifully. And of course, we recommend NO weed barrier beneath.

The optimal type of gravel will vary for pathways and planting beds. Gravel in the planting beds can be rounder, and perhaps even smaller — as small as 3/8-inch diameter, and as round as a beach pebble. Our favorite simple gravel for mulch in planter beds is 3/8-inch to 1-inch Del Rio pebble, but pretty much anything will work.

For pathways, there are more basic rules. First, gravel pathways are best installed over a stabilized base — stabilized compacted soil, decomposed granite or a plastic grid like a grasspave work the best, and only about 3/4-inch to 1-inch depth is required. Second, gravel pathways must be contained with a barrier that rises 1 inch above grade at a minimum. We like stone edging (classy and very Mediterranean), but bender board, aluminum or steel edging would work too. Third, and perhaps most important, the type of gravel needs to be the sharper-edged gravel, not the rounded beach stone. The sharper gravel will grab on to its neighbor and become firmer and easier to walk on than the rounded stones.

(Photo: Flower to the People)

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