Using Rocks as Mulch: Pros and Cons

Mulch is any material that is used as a covering for soil.  It is used to help retain moisture, suppress weeds, regulate soil temperature, and more!   Another reason we use mulch is to enhance the visual appeal of our landscape or garden.  While there are many types of mulch (both organic and inorganic), two types of mulch are the most commonly used.  These are shredded wood (or bark) and landscape rocks.  In this blog, we are going to focus on landscape rocks and the pros and cons of using them as mulch.  

The Pros of Landscape Rocks as Mulch

There are many benefits to using rocks as mulch:

• Sturdy and durable – they are far less likely to wash away because of rain or blow away in the wind
• Cost saving – they do not break down like organic mulch, and you rarely have to replace them
• Variety – rocks come in many shapes, colors, sizes, and textures
• Weed prevention – rocks, especially when used with weed mat, are generally better at suppressing weeds than most organic mulch

The Cons

Here are some reasons why using rocks as mulch may not be a good idea for your landscape:

• Heat – rocks have a tendency to raise the temperature of soil, which can stress certain plants
• pH levels – rocks change the pH level of soil to more of an alkaline, which can affect certain plants
• No nourishment – because rocks do not break down, they do not nourish the soil

Making a Decision

If you are considering rocks over something organic, take this list of pros and cons into consideration.  Certain plants and conditions are not ideal for using rock as mulch, but, in the end, it will come down to a matter of preference.  The unique aesthetic offered by using rocks may far outweighs the cons!