Here in the Southwest, gravel has long been a part of our landscapes. Desert gardeners know the benefits and pitfalls of this natural material, which is available in many colors, sizes and pebble shapes.
Now gravel has become a national obsession. It’s hot stuff in modern gardens for filling gaps between contemporary concrete pavers. Elsewhere, it’s used in lieu of mortar between flagstones of all shapes and sizes. Still other landscapes have gravel walkways often used as secondary paving in side yards.
What makes gravel so widely appealing is its low cost and the colors and textures available. You need not be limited to typical gray pea gravel. Visit a gravel yard to see firsthand what’s immediately available. Note that some gravels are uniform in color while others are a mixture of hues that may fit better with your project. You’ll also see the difference between sharp crushed gravel and pebbles rounded by water.
This is all rooted in the “green” concept of permeable paving. Unlike poured concrete, gravel walking surfaces allow water to pass through and percolate down into natural soil underneath. The ground acts as a giant filter, catching pollutants so water moving through is cleaner when it reaches the water table. The problem with surface runoff from solid paving is that it carries debris and toxins into storm drains that later deliver a payload of crud into nearby waterways.
If you’re thinking of using gravel for your next landscaping project, beware of the pitfalls that desert landscapers learned to avoid long ago.
- Litter. Organic matter from plants, be it leaves or lawn clippings, settles into the nooks and crannies of gravel surfacing. This is a problem with gravel that’s dark in color; every bit of detritus stands out like a sore thumb. Organic matter also filters down between the stones to gather underneath where decomposition creates fertile ground for weeds.
Use fine-textured gravel that packs tighter and is easily raked or blown clean. Choose a light-hued gravel with variable colors so litter won’t stand out.
- Traveling. Gravel has been known to travel outside its designated area under the pressure of foot traffic. Sloping ground also results in buildup at the bottom of an incline due to gravity. Avoid river-rounded pebbles; they are more likely to travel compared to crushed gravel, which has sharper edges that hold fast.
- Kick and track. Surfaces such as decomposed granite or crushed sandlike gravel are often kicked into other areas or tracked far and wide on shoe soles. This could be a problem if interior floors are wood or tile, which could be easily scratched by the sharp stones picked up in shoe treads. Avoid gravels finer than a quarter-inch for walking surfaces or as filler between pavers or flagstones.
Page 2 of 2 - - Soil. Know your soil before selecting gravel. Where the ground is dense, it becomes soft when wet. All gravel will sink into moist clay from the weight of foot or vehicle traffic. Over time, more gravel becomes embedded deeper and deeper as your surface layer grows progressively thinner.
To separate such soils from gravel, lay a sheet of heavy weed-barrier fabric (not plastic) over the designated area before spreading pebbles. It acts like a barrier to keep gravel separated from your soil while remaining permeable so water still moves through. This fabric is essential in areas that were former lawns to prevent perennial grasses from returning to infest your gravel.
Gravel can be a great alternative or a real nightmare, depending on your choices. Don’t let your gravel sink, travel or sprout weeds. Follow these guidelines to help make your project as successful on day one as it will be a decade down the road.
Maureen Gilmer is an author, horticulturist and landscape designer. Learn more at www.MoPlants.com. Contact her at firstname.lastname@example.org or PO Box 891, Morongo Valley, CA 92256.