Black Shredded Mulch vs River Rock: Size, Cost, and Which to Use

Black Shredded Mulch

Shredded hardwood mulch dyed black for a bold, modern landscape look. Rich black color makes green plants and colorful flowers stand out. Holds its color longer than brown mulch and provides the same moisture retention, weed suppression, and soil temperature regulation benefits.

River Rock

River rock is naturally rounded stone from river beds and glacial gravel deposits, washed and screened into size bands from 3/4 inch to 8 inches. It costs $40 to $100 per ton in 2026, weighs 1.35 to 1.6 tons per cubic yard, and is the go-to decorative stone for dry creek beds, garden beds, borders, and drainage swales where the rock needs to look good and stay put. It costs two to three times what crushed stone costs because it is sorted and washed, and because the supply is limited to places with river gravel.

Black Shredded Mulch

• ✓ Landscape beds
• ✓ Tree rings
• ✓ Garden borders
• ✓ Foundation plantings
• ✓ Commercial landscaping
• ✓ Contrast beds

River Rock

• ✓ Landscaping
• ✓ Dry creek beds
• ✓ Decorative borders
• ✓ Drainage swales
• ✓ Water features
• ✓ Ground cover

Black Shredded Mulch

• + Bold black color creates striking contrast with plants
• + Holds color longer than natural brown mulch
• + Retains soil moisture reducing watering
• + Suppresses weed growth naturally
• + Insulates soil temperature

• − Dye can temporarily stain hands, concrete, and clothing
• − Needs replenishing every 1-2 years as it decomposes
• − Can attract termites if placed against structures
• − Fades to dark gray over time
• − Slightly more expensive than undyed mulch

River Rock

• + Best-looking bulk stone, natural mixed colors
• + Never decomposes, one-time install
• + Drains fast and rarely clogs
• + Large sizes stay put in moving water
• + Available in sizes from 3/4 inch to 8 inch cobbles

• − Expensive, $40 to $100 per ton
• − Never packs, so it is a poor surface to walk or drive on
• − Heavy and awkward to spread
• − Holds heat in full sun
• − Hard to clean leaves and debris out of

Black Shredded Mulch

Shredded strips of bark and wood, typically 1-4 inches long, dyed with carbon-based black colorant. The dye is non-toxic and safe for plants and pets. Double-shredded black mulch mats together better and resists displacement.

River Rock

River rock is sold by size band: 3/4 to 1 inch (sometimes called large pea gravel), 1 to 2 inch (egg rock), 2 to 3 inch, 3 to 5 inch, and 5 to 8 inch cobbles. Every piece is smooth and rounded. Colors are a natural mix of tan, brown, gray, cream, rust, and black, with regional loads that run mostly one shade. Single-color sorted rock costs more.