Choosing River Rock or Mulch


These days you are spoiled for choice when it comes to ground cover, you can opt for synthetic material, such as landscape fabric and recycled rubber strips, or go for natural organic mulch and natural inorganic mulch. The benefits of a ground cover like river rock or wood mulch is weed suppression, water retention and aesthetic appeal. While mulch reduces erosion and water loss, improves soil nutrition and a more balanced soil temperature, attractive river rocks prevent weed growth, helps conserve water and requires little maintenance. Read about their advantages to decide for yourself, which ground cover would be suitable for your landscaping and design needs.

Cost and Durability

Organic mulches ranging from shredded bark, pine needles, pine bark wood chips, cypress, or compost are much less expensive than river rock. But you also need to consider that river rocks do not decompose and therefore do not need to be replaced, which makes river rock a better durable solution for permanent installations over time. River rocks may be used around trees and shrubs but organic mulches are better for gardens with perennial or annual plants. Rock ground covers have staying power. Durability may be a central consideration for areas like the walkways or a driveway, where rock ground covers will have more staying power to heavy use as against organic covers that may be easily trampled over.

Maintenance Requirements

Organic mulches need regular maintenance because they decompose. They have to completely removed and replaced every few years because the wood’s color fades and also before they build-up and smother plants. River rock does not need to be constantly replaced, but may need periodic washing with a garden hose or topping up with a new upper layer of stones when they get blown away by the wind or displaced by pets. Even non-living, organic ground covers need periodic maintenance.

Soil Nutrition

Mulches made from organic materials contribute to nutrients in the soil, such as nitrogen and phosphorous, when they decay over time. This added soil nutrition is vital for trees and other plants. River rocks do not provide any additional nutrition or improve the soil quality.

Water Conservation

River rock mulch can reduce water loss in areas where conservation is a big concern. A research study by the University of California showed that small stones held only 0.09 inches of water per 1 foot of mulch while for bark and other organic material it is between 1 and 3.64 inches per 1 foot. Using rocks can stop erosion, slow down water loss from the soil below, and bring down the use of water during hot months, reducing the consumer’s water bill.

Weed Control

River rocks offer effective weed control when used in combination with landscape fabric, whereas weeds can grow aggressively through organic mulch. Organic mulches need regular de-weeding unless you choose something like eucalyptus, which checks the growth of young plants.


Mulch can pose a real fire hazard, especially in wildfire prone areas. Fires can spread quicker through organic mulches, whereas river rocks and crushed gravel are fireproof. It is best to avoid using organic mulch within five feet of homes in regions plagued by wildfires. You can replace mulching materials with rocks, gravel, pavers, or brick chips. Rocks can get much hotter than wood mulch because it absorbs sunlight and retains heat, which can be uncomfortable for plant growth.

Contact Davis Concrete at (800) 910-6928 for all your landscaping supplies. We can help you choose the right landscaping material for your backyard.



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