Side by side
| Wood mulch | Landscape rock | |
|---|---|---|
| Bulk price per cubic yard | Often $25 to $50 | Often $45 to $150+ |
| Covers at 3 in deep | About 108 sq ft per yard | About 108 sq ft per yard |
| Weight per yard | About 0.3 tons | About 1.4 tons |
| How long it lasts | Breaks down; top up every 1 to 2 years | Many years; add a little as it settles |
| Effect on soil | Keeps it cool and moist, adds organic matter | Adds nothing; stone holds and gives off heat |
| Weeds | Blocks light; weed seeds sprout on top over time | Needs landscape fabric; leaves and dirt collect between stones |
| Fire | Can burn | Will not burn |
| Best for | Flower beds, shrubs, trees, vegetable gardens | Dry gardens, succulents, beside the house, areas that need little care |
Prices are typical bulk ranges before delivery and vary by region. Weights are from our weight chart.
Cost now and over five years
Take a garden bed of 200 sq ft covered 3 inches deep. That is 50 cubic feet, or about 1.85 cubic yards, of either material. The mulch calculator and landscape rock calculator give the same volume for any shape.
| Mulch at $35 a yard | Rock at $90 a yard | |
|---|---|---|
| First year | About $65 | About $165, plus $25 to $40 of fabric |
| Each later year | About $22 to top up 1 in | Little or nothing |
| Five-year total, bulk, spread yourself | About $150 | About $200 |
Delivery fees are left out of the table; with a small order they can be the biggest cost. If you spread it yourself from bulk, mulch often stays the cheaper choice for years. The picture changes if you pay a landscaper to re-mulch every season, buy mulch in bags, or choose a pricey dyed mulch. Then rock usually wins within a few years.
When mulch is the better choice
- Around plants that like rich, moist soil: most flowers, shrubs, trees and vegetables.
- When you want to improve poor soil; mulch slowly feeds it as it breaks down.
- On a tight budget for the first year.
- When you will be moving it by hand. A yard of mulch weighs about a fifth of a yard of rock.
When rock is the better choice
- Dry and desert-style gardens, cacti and succulents.
- Right next to the house in wildfire-prone areas, where fire services often advise keeping the first few feet free of anything that burns.
- Windy spots or under downspouts, where mulch blows or washes away.
- Areas you want to leave alone for years.
Be careful with rock in full sun next to plants that dislike heat: stone soaks up heat during the day and gives it off at night.
Getting the depth right
Aim for about 2 to 3 inches of either. Thinner lets weeds through; much thicker mulch can keep water and air from reaching roots. Keep mulch a few inches back from tree trunks and plant stems, and never pile it up against them, because constant damp bark invites rot and pests.
For rock, lay landscape fabric first, overlap the edges, and use edging so stones stay out of the lawn.
Can you mix them?
Yes, and many yards do: mulch in planted beds, rock along the foundation, paths and drainage areas. Use a firm edge between them, or the two will slowly mix.
Common questions
Is rock or mulch cheaper?
Mulch is cheaper to put down. Rock costs more at the start but lasts for years, while mulch needs topping up every year or two. If you spread bulk mulch yourself, mulch often stays cheaper for five years or more; rock tends to win if you pay someone to re-mulch each year.
Is rock or mulch better for plants?
Mulch, for most plants. It keeps soil cool and moist and adds organic matter as it breaks down. Rock suits cacti, succulents and dry gardens.
Should I put rock next to my house?
In wildfire-prone areas, many fire services advise keeping the first few feet around the house free of mulch and other things that burn. Rock or gravel works well there.
How deep should mulch and rock be?
About 2 to 3 inches for both. Keep mulch a few inches away from tree trunks and stems.