Pros & Cons of Rocks vs. Mulch in Landscaping

After planting new trees, flowers, and shrubs the next step is to add the finishing touch – mulch. Mulch is what makes the landscape look polished and pristine. The question most people ask, however, is this: does the kind of mulch used really matter? Can the mulch be replaced with stones? The purpose of this post is to answer these two questions by looking at the pros and cons of rocks versus mulch in tree care.

Organic Mulch

  • Pros

    • Better growth: Mulch doubles the rate at which the trees grow. This is according to a study by Kansas State University.
    • Less water: Mulch will reduce the evaporation so that you don’t spend a lot of time and money watering.
    • More nutrients: As it breaks down, mulch will release nutrients that plants need to grow.
    • Fewer weeds: Mulch will keep weed seeds from growing. You will notice 50% fewer weeds.
    • Regulates temperature: Mulch will keep your plants warm during winter and cool in hot summers.
    • Reduce erosion and compaction: Mulch has been found to reduce erosion by a whopping 85%. People are less likely to step on the mulch hence less compaction of the soil.

  • Cons

    • Annual replacement: Mulch has to be replaced once every one to four years. It depends on the type of mulch you are using. This means mulch is a recurring time and money expense.
    • Too much of a good thing: Adding a thick layer of over 3 inches will stress out a plant.
    • Mulching too early can lead to late blooms. When you mulch too early you might slow how fast the ground warms. This might lead to late blooms.
    • Mulching too late leads to weeds: Mulching will keep weeds from growing. However, if you are late in mulching, mulching might not stop the weeds from germinating.
    • Check for seeds: Some of the organic mulches such as hay and pine bark may contain seeds which might grow.

Rocks In Your Garden

  • Pros

    • Low maintenance: You will almost never have to replace them.
    • Low cost: Since rocks are long-lasting, they are less expensive to use and maintain than mulch.
    • Fireproof: Rocks are non-flammable hence ideal for areas with wildfires.
    • Can eliminate weeds: Rocks will keep the weeds away much longer.
    • Wind-resistant: Heavy rocks will prevent soil erosion in windy areas.
    • Perfect for cacti and rock gardens.

  • Cons

    • Too hot: Rocks, more so the lighter ones, will increase soil temperature thus causing plants to be stressed and thirsty.
    • No benefit to the plants: Rocks will not aid soil health or plant growth.
    • Messy pH: The majority of trees need acidic soils but rocks will make the soil alkaline. This can hurt the trees.
    • Weeds will eventually grow: Weeds will eventually grow between the rocks.
    • Not good for pruning: They can bar rejuvenation pruning leading to unwieldy shrubs.
    • Remove by hand: Removing rocks has to be done manually.

Your choice of mulch or rock will depend on what you want. All the same, mulch is a better choice whereas rock is better than having no mulch at all. 

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