Mulch vs. Rock vs. Soil: What’s Best for Your Planter Beds?

You’ve got your new plants in the ground, your beds are looking great—but there’s one last decision to make: what do you put on top?

Mulch? Rocks? Or maybe just a layer of soil?

Let’s walk through the pros and cons of mulch vs. rock vs. soil for your planter beds and landscaping around the house — so you can make the best call for your yard.

Mulch: The Tried-and-True Favorite

When it comes to landscaping around bushes, trees, or flower beds, mulch is a classic — and for good reason.

The Pros of Mulch:

• Keeps soil moist longer: You’ll water less, which your plants (and your water bill) will love.
• Protects roots: Mulch helps insulate soil — cool in summer, cozy in winter.
• Prevents erosion: It keeps soil from washing or blowing away.
• Feeds your soil: Over time, mulch breaks down and improves soil health. Worms and microbes love it.
• Fewer weeds: A thick mulch layer makes it harder for weeds to push through.
• Looks neat and natural: Whether you go for dyed mulch or shredded bark, it gives your beds a clean, cohesive look.

A Couple Things to Consider:

• It’ll break down over time, so you’ll want to top it off every year or two.
• Lighter mulch can blow away in windy areas.
• Average cost of mulch: $40-$50 per yard, not including delivery or installation.
  
  

Decorative Rock: Looks Good, Lasts Longer… But

Thinking about using rocks instead of mulch around trees or beds? Rocks can be low-maintenance at first — but they’re not always as carefree as they seem.

Rock Mulch Pros:

• It stays put: Wind? No problem.
• Long-lasting: No need to reapply like mulch.
• Great for drainage: Especially helpful in areas with excess water.
• Nice, modern look: River rock, lava rock, or crushed gravel can add style to your landscape.

But Here’s the Flip Side:

• Holds heat: Rocks absorb and radiate heat—this can stress plant roots, especially in summer.
• No nutrients: Rocks don’t break down or improve soil.
• Weeds still happen: Dirt and debris build up over time, and yes—weeds grow through rocks too.
• Tough to change later: Removing rocks isn’t fun if you ever want to redo the bed.
• Cost of decorative rock: Basic gravel runs $12–$15 per yard. Decorative rock can be $80–$110 per yard.

Soil for Planter Beds

When you consider mulch vs rock vs soil, it’s tempting to just choose soil. It’s already there, right? What could be easier? But there are some disadvantages.

The Pros

• There’s no extra cost to just leave your beds bare.

The Cons of Using Just Soil

• Dries out quickly: You’ll be watering way more often.
• Washes away: Rain and wind can erode your soil and expose plant roots.
• Weeds love it: Nothing’s stopping them from taking over.
• It’s not pretty: A bare bed usually doesn’t look intentional or tidy.
  
  

Rethinking Rock: It’s Not Always the Easy Button

Many homeowners switch from mulch to rock because they’re tired of refreshing it. But “rock is permanent” can be a trap.

We’ve had clients call us years later, frustrated with:

• Sinking rocks
• Weeds poking through
• Landscape fabric needing to be replaced
• And the huge job of digging it all back up

Rock has its place — like around foundations, in high-traffic areas, or as a fire-resistant ground cover in dry climates — but it’s not the best choice if you want healthy, plant-friendly beds.

Have Kids or a Play Area?

If you’ve got a swing set or play zone, choose playground mulch — like soft wood chips or rubber mulch. It’s safer for little feet and minimizes slivers.

Our Landscaping Pro Tip for Idaho Falls

For most Idaho homeowners, we recommend mulch for planting beds. It’s affordable, looks great, and supports your soil over time.

Decorative rock can work in specific areas — especially for xeriscaping, around foundations, or places you don’t plan to plant — but it takes planning.

Bare soil? Skip it. It’s just an open invite to weeds and erosion.

Need Help Deciding? Let Outback Landscape Take a Look

Still debating mulch vs. rock? Wondering what’s best for landscaping around your house?

We can take a look at your space and help you make the right call — based on your plants, layout, and goals. We’ll even do the install for you.

Outback Landscape is based in Idaho Falls, and we serve Rexburg, Pocatello, Rigby, and the surrounding areas.

Call us at 208-607-3776 or contact us here to set up a free consultation.

Let’s make your planter beds the best-looking part of your yard.