What Are The Pros And Cons Of Lava Rock Landscaping?

Paige Hanawalt
by Paige Hanawalt

When it comes to gardening, we all want a landscape that not only looks beautiful but is also well taken care of. Mulch— no matter what kind— is necessary for a garden to flourish. Many gardeners are looking to lava rocks for their aesthetic and practical appeal.

Available at any home improvement store, this inorganic mulch will give your garden a unique, finished look. Lava rocks come in many different colors, including black, pink, grey, and reddish-brown. It’s a great way to add a little character to your back or front yard.

Quite popular in more arid regions, lava rock is the most popular inorganic mulch when it comes to xeric landscaping. Xeric landscaping, or xeriscaping, is a type of gardening designed specifically for areas where drought or water conservation are major concerns. You’ll find lawns littered with lava rock in states like Arizona, Utah, and even Colorado.

There are a few pros and cons to look at when trying to decide if volcanic rock landscaping will work for you.

The pros of lava rock landscaping are that it acts as a natural weed suppressant, absorbs and retains both heat and moisture, and is both affordable and multifunctional. Cons of lava rock landscaping are that it will not add nutrients to the soil, doesn’t decompose, and the specific aesthetic of lava rocks might hinder your curb appeal.

Read on to see if lava rock landscaping is a good fit for your garden!

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What Are The Pros Of Lava Rock Landscaping?

Lava rock landscaping is on the rise. Many horticulturists are turning to this distinctive and interesting mulch alternative for their gardens.

Natural Weed Suppressant

Weeds are the natural enemy of any garden and its gardener. Weeds can seemingly shoot up out of nowhere, choking the life out of carefully planted tomatoes or gardenias. While spraying for weeds is always an option, it can be damaging to the very plants you’re trying to protect. Lava rocks work as a natural weed suppressant.

Because they are heavier and more solid than a layer of wood chips, lava rocks make it more difficult for weeds to break through. If you don’t use a layer of fabric below your lava rocks on top of the soil, some weeds may still poke through the soil to wreak havoc on your garden.

The number one defense against weeds in your lava rock is landscape fabric. When combined with landscape fabric, lava rock landscaping will allow water and air to reach your plants, but blocks most types of weeds from sprouting.

Lava rocks and landscape fabrics can’t be beat!

Keeping Things Weed Free!

Follow these simple steps below to make sure your garden is weed-free this spring and summer:

Step 1: Using a gardening knife, spade, or claw pull up any weeds and dispose of them. Be sure to get the entire root of the weed.

Step 2: Measure around your garden bed with a tape measure and cut your landscape fabric to match. Cut an X shape into the fabric wherever a plant will be, making sure the X is big enough to fit over each plant. X shapes will vary based on the different types of plants you have.

Step 3: Lay the fabric over your garden bed, folding the X shape flaps of fabric around the base of the plant to create a square shape.

Step 4: Cover the fabric with your lava rocks, avoiding the base of the plant. If weeds do sprout, they will come around the base of the plant and can easily be yanked.

Absorbs And Retains Heat And Moisture

Lava rocks are unique in that they are able to both absorb and retain heat and moisture, necessary elements for any flourishing garden. Porous and light, lava rocks absorb heat during the day and release it at night. They will block moist soil from the sun during the day and then redistribute that warmth during the cool of the evening. Lava rock landscaping is the perfect natural temperature regulator.

Because of their porous nature, lava rocks are also perfect conduits of moisture. They will retain moisture and provide excellent drainage, making sure your plants are rarely dry and brittle. Here are a few plants that flourish beautifully in a lava rock landscape:

  • Variety of succulents: sedum, sempervivum, jovibarba
  • Tomatoes
  • Orchids
  • Spleenwort
  • Rabbit’s-Foot Fern

Affordable And Multifunctional

Because lava rock is so lightweight, it is less costly to transport and so is readily available at most home improvement stores. You’re looking at paying around $7 per bag, which, when compared to other readily available rock mulches, is fairly comparable. Delivery and installation will go by more quickly since lava rocks are extremely lightweight— so much so that they even float in water.

You’ll want to showcase your lava rock, so make sure you choose a smaller garden bed or an island garden bed. Because it’s so unique and eye-catching, it works wonderfully as a focal point in a larger garden.

If you’re looking to get more bang for your buck, lava rock is the best way to go. Not only can it be used in garden beds, but it is also great for:

  • indoor plants
  • barbecue pits
  • ponds

What Are The Cons Of Lava Rock Landscaping?

Even though landscaping with lava rock offers many benefits to your garden, there are a few drawbacks you might want to consider before ordering in bulk.

May Block Nutrients

The very characteristic that makes lava rock ideal for plants is also what makes it potentially unideal. Lava rocks might create an inhospitable environment for plants to grow. Because of its absorbent nature, lava rocks may hold onto necessary nutrients the plants need.

While it excellently blocks weeds from sprouting, it can also hinder new plant growth. That’s why there are really only specific types of plants that really flourish with lava rock landscaping. Perennial flowerbeds won’t mesh well with lava rocks.

Difficult To Clean

It can be more difficult to remove branches, leaves, and debris from lava rock beds. Debris can get caught between the rocks and stay there. Not clearing out the garden bed will give it a messy, disorganized look. Once lava rocks have settled into the soil, they can be difficult to dig out and move, making the cleaning process that much more tricky and time-consuming.

Doesn’t Decompose

Because lava rock doesn’t break down over time, it won’t improve the soil structure or add nutrients naturally. Other mulch options need to be replaced over time because they break down. Lava rocks are a permanent addition to your garden bed and won’t need to be replaced.

While this may seem like an advantage, there are times when the permanence of lava rocks can be frustrating. If you’ve made the commitment and your plants aren’t flourishing, removing lava rocks can be extremely difficult. Lava rocks can sink into the soil over time, its inorganic makeup making it harder to dislodge from its environment.

Hinders Curb Appeal

There’s no way around it; lava rock landscaping isn’t everyone’s cup of tea. It usually comes in more earthy tones like reddish-brown, black, or grey. That’s why more desert regions use lava rock landscaping. Its inhospitality to some of the more colorful, perennial plants, means that you will be restricted when it comes to the types of plants that will flourish in a lava rock landscape.

Because lava rock landscaping is such a specific aesthetic, real estate agents sometimes have a hard time showcasing a home that features this particular type of xeriscaping. If you’re concerned about curb appeal and the resale value of your home, consider that lava rock landscaping may seem unappealing to some and is very costly to remove.

Related Questions

Is Lava Rock Good For Landscaping?

Lava rock works best when it mirrors its surrounding terrain. Depending on where you live and what kind of garden you’re after, lava rock could fit your landscaping needs.

How Long Does Lava Rock Last?

Lava rock doesn’t decompose. Essentially, in a garden bed, lava rocks can last an indefinite amount of time. If you’re using lava rocks in a barbecue pit or a pond, you are looking at about 2-3 years of regular use before they start to disintegrate.

Are Lava Rocks Safe For Vegetable Gardens?

Depending on the vegetable you’re trying to grow, yes. Lava rocks are great for tomato plants. The natural nutrients in the lava rocks themselves feed tomato plants specifically, helping them grow fuller and taller in a single season than if you were to use regular mulch.

Do You Need Landscaping Services?

Get free, zero-commitment quotes from pro contractors near you.

Our Takeaway

Lava rocks really are an excellent option when it comes to making sure your landscape will flourish and look good doing it. Because lava rock landscaping is such a specific aesthetic, you’ll want to carefully weigh all pros and cons before making the commitment. If xeriscaping is your thing, then lava rock landscaping would be the perfect fit for your outdoor oasis.

Paige Hanawalt
Paige Hanawalt

Paige is an elementary school librarian with a passion for writing. Her hobbies include reading an exorbitant amount of fantasy, slowly teaching herself to draw, and home decor. While she isn't the most talented artist or interior designer, what she lacks in skill she more than makes up for in enthusiasm. When she's not curled up with a book, you can certainly find her curled over the keyboard.

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