Lava Rock Landscaping Problems

Disclosure of Material Connection: Some of the links in the post above are "affiliate links." This means if you click on the link and purchase the item, I will receive an affiliate commission. Regardless, I only recommend products or services I use personally and believe will add value to my readers. I am disclosing this in accordance with the Federal Trade Commission's 16 CFR, Part 255: "Guides Concerning the Use of Endorsements and Testimonials in Advertising."

Lava rocks are becoming more popular in yards and gardens, mostly as mulch. But if you’re thinking about using them in your yard there’s also lava rock landscaping problems to consider before you make a final decision.

Lava Rock Landscaping Problems

The most common application for lava rocks used to be on your propane or gas fire pit. But their versatility has helped them become more popular all around the yard.

Unlike masonry and stones, lava rocks are known for their durability when used for hardscape. There are also some nice colour options to help you reach your aesthetic goals.

They’re also great as mulch because they drain well and are soft enough that plants can still grow around them. When paired with a fabric weed barrier, lava rocks are also great weed suppressors.

Lightweight and relatively inexpensive, you end up with something that’s both durable over the long term and easy to work with. 

All this sounds great, but there are problems landscaping with lava rocks too. These are the most common issues that come up in residential yards. 

What Are Lava Rocks?

Most lava rocks are mined from ancient volcanoes that erupted a long time ago and have since left huge magma deposits. That’s what they mine for the lava rocks we use in landscaping.


Lava rocks are a misnomer. They’re usually a type of volcanic rock like basalt or pumice, or it could even be used to describe rocks that just look like they’re from a volcano but are actually other types of rocks altogether. 

Lava Rocks Are Lightweight

This sounds like a perk when you’re picking them up from the store or lugging a bag of lava rocks into your backyard – but lightweight isn’t a good thing in nature. If you live in a windy area, lava rocks can easily be moved around by the wind if there’s nothing else to secure them.

They’re also susceptible to disruption in wet or high rainfall conditions, especially if water tends to run in your yard. Even the lawn mower can kick them up if you’re not careful.

A Hazard for Mowing

Speaking of, lava rocks (like any type of hard and loose landscaping material) can cause personal injury if you’re mowing. Make sure your yard is cleaned up and you avoid beds with lava rocks in them.

Good edging when you make your lava rock beds can help with this. 

More Expensive Than Mulch

While lava rock can be cheaper in the long term, the upfront costs are a lot higher than traditional mulch. Mulch often needs replacing each year (or at least, you need to add more as it wears down) whereas lava rocks are often considered to be permanent. 

That being said, though, the initial buy in can be a big strain on your landscaping budget.

Lava Rocks Sink Into the Ground

If you’re dreaming of a lava rock pathway instead of gravel you’re going to be disappointed. The best you can do is use the lava rock as filler between patio stones. That’s because lava rock sinks into the ground, especially when you step on it.

You can alleviate this problem a bit by adding a sturdy layer of landscape fabric. This will not only help keep the rocks on top of the soil, it also prevents weeds. 

Once they get embedded in the soil lava rocks are pretty difficult to remove. 

Hard to Move

Since they stick into the ground lava rocks are also notoriously hard to move. In some cases you’d even have better luck just digging them out with a skid steer and starting again. 

Basically, make sure you’re happy with the location before you start!

They Reflect Light and Absorb Heat

One big lava rock landscaping problem is that the colour you choose will create different growing conditions. Lighter colours will reflect the light away from the rocks and onto the plants. Darker rocks, on the other hand, absorb heat and raise the temperature of the soil.

You should check the growing conditions of your plants before picking your lava rock colours.

Can Be Hard to Clean

If twigs and other yard debris fall into your lava rock beds they can be a pain to clean up. Especially if you have a large area that you don’t want to walk on. Because of their texture they might also cling onto dirt and mud.

Lava Rocks Don’t Decompose

While this can be a perk if you’re looking for a permanent solution, the lack of decomposition means that lava rocks will have to be removed manually. They will, however, erode over time.

When mulch decomposes it actually helps improve the quality of the soil. Lava rocks are also mineral rich, but since they’re much hardier they don’t get the chance to really benefit the soil quality as much.

Not Everyone’s Aesthetic 

Red lava rocks are pretty common and look distinctive in your yard or garden. Some people love them, others really dislike the look. If you’re thinking of selling your house in the future lava rocks might not be the best option.

You should also make sure they’re approved by your HOA (if applicable) – some have strict rules about mulch colours.

Lava Rocks Aren’t Good for All Plants

When used as mulch, lava rocks are great for drainage. But depending on the climate in your area and what you’re trying to grow, that drainage can actually hinder your plants.

Since lava rocks are organic you can usually plant anything that does well in much. Lava rocks around the base of trees and shrubs are fine, for example. If you have a lot of perennials, though, any mulch including lava rocks can hinder their growth.

Likewise, putting too much mulch in your flower beds could make it harder for plants to grow too. 

Lava Rock Landscaping Problems – Final Thoughts

Most lava rock landscaping problems can be overcome by careful planning. If done right, they’re a great, low maintenance investment for your yard. Lava rocks are also environmentally friendly and an ideal mulch substitute or accent rock for most climates.