Decorative gravel is becoming the green, sustainable alternative to lawn. It’s also a useful problem solver for dozens of scenarios in the ordinary landscape. In some regions such as the Southwest, it’s long been in use for surfacing open spaces in sparsely planted desert gardens. In the 1970s, colored gravel and evergreens became the low maintenance solution to prolonged drought. Today new and innovative ideas for gravel in the landscape are implemented to create unique design compositions, to save water and eliminate high maintenance lawns.
Cobble is technically a gravel but is much larger and used a different way in the landscape. These larger stones are either crushed or river run, and must be hand placed due to their size. They are not suitable for walking surfaces for pets or people, but their chief value is dividing large fields of small gravels with a color and or textural difference. Landscaping rocks and cobbles are rocks that can enhance the look of your landscape project while providing practical benefits. Landscaping rocks and cobbles typically measure 2.5 inches to 10 inches in diameter.
Pea gravel has a natural look, helps to minimize soil erosion, contours to follow any path through a landscape and repair costs are minimal compared to concrete. Pea gravel walkways have always been a great choice for homeowners and property managers alike. The gravel path is eye-appealing and will connect your outdoor living space with your gardens. Crushed stone and pea gravel are two “hardscape” materials that can be used in many applications in the construction and agricultural fields. Crushed stone comes in a wider variety of sizes and generally costs a little more than pea gravel. Pea gravel has a more attractive appearance and the stones are typically smaller than crushed stone.
This is any gravel product that is crushed from larger rock in a quarry. Once crushed, the material is fed through a sieve to separate out particles of a certain size. Sieves can range from two inch particles to those less than a quarter inch known as “fines”. Crushed gravel has sharp edges that help it remain in place, particularly for walks and driveways on a gentle slope. When weighted down the particle’s sharp edge is pressed into the ground for anchorage.
River Run Gravel
The term river run is applied to any type of gravel composed of naturally occurring rounded particles. These may be shaped by eons in the surf or fast moving river water. This product is not changed in any way except size. It too is poured through sieves to achieve a certain size overall. Some river run gravels from beaches are available in a single size while others such as the black Mexican beach pebbles can range widely in size.
As popular as they are in contemporary landscapes, mulches are not a new concept. For as long as trees have grown in forests, leaves and needles have fallen to the ground, matted together, and formed a natural protective layer over the soil.
The English word mulch is probably derived from the German word molsch, meaning soft, beginning to decay. It no doubt referred to early gardeners’ use of straw, leaves, and loose earth spread on the ground to protect the roots of newly planted trees and shrubs.
Many different natural and synthetic mulches are available today, but all perform at least three basic functions:
Reduce soil water losses.
Protect against temperature extremes.In one study comparing various mulch materials with bare soil, soil moisture percentages in mulched plots were approximately twice as high, summer soil temperatures were reduced by 8 to 13 degrees, and the average amount of time required to remove weeds was reduced by two-thirds.
The use of mulches in landscape plantings provides other benefits as well. When water droplets land on bare soil, the impact causes soil particles to fly in all directions, resulting in soil crusting and slow water infiltration. Most mulches break the impact of the droplets, reducing soil erosion and crusting and increasing the penetration of water into the soil.
In addition, mulches improve soil structure in several ways. As organic mulches decompose, they provide organic matter that prompts soil particles to aggregate. Large aggregates increase aeration and improve moisture conditions in the soil. These conditions, in turn, encourage additional root development and biological activity, further enhancing soil structure.
ARS Landscape Materials & Supply, Denver, Colorado