Rock vs Mulch

Ground covering is used by gardeners for several different reasons.  It can help inhibit the growth of weeds, prevent soil erosion, reduce water evaporation or just plain make the area look nicer.  When it comes to choosing a type of ground covering, gardeners have long asked themselves, “Rock vs mulch:  Which is better?”  In this post, we’ll go over the advantages and disadvantages of each type of ground covering.


If you’re comparing rock to a plant-based mulch made of wood fibres or other biodegradable material, rock is obviously the much more durable choice.  Biodegradable mulches will break down over time and will need to be eventually refreshed.  Rock will last as long as you’re happy with it.

Moisture Retention

One of the more popular reasons for using mulch is to prevent water evaporation and help the soil retain its moisture.  Biodegradable mulches may have an advantage over rock ground covering in this respect as they can absorb moisture which will add an extra layer of protection against water evaporation.  Using rocks to cover the ground will also slow water evaporation from the soil, but they will not retain any moisture themselves.

Weed Management

When comparing rock vs mulch for weed management, both types of ground coverings will help slow down the proliferation of unwanted plant growth.  They both prevent sunlight from reaching the weed shoots while also providing a physical barrier against growth.  Although neither type of ground covering will eliminate weed growth altogether, they’re both similarly effective at curtailing weed propagation.

Soil Maintenance

Another popular reason for using a ground covering is to reduce soil erosion.  Soil can be broken down and carried away by regular watering, rainfall, heavy winds and other extreme weather conditions.  When comparing rock vs mulch ground coverings, both are quite effective at preventing soil erosion, although extreme conditions might be too much to completely protect the soil from being carried away.


Quite often ground coverings are used for purely aesthetic reasons.  As beauty is in the eye of the beholder, comparing rock vs mulch ground coverings from an aesthetic viewpoint comes down to personal preference.  Both types of materials can be used to great aesthetic effect.