Which mulch works best for slopes and erosion control?
Written by
Liu Xiaohui
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Mulched sloped gardens require special mulch solutions that help with soil loss. Shredded bark, for example, provides a natural net to catch soil on slopes, and Coconut coir mats can be used - similar to erosion blankets - for very steep slopes. After heavy rains washed away my topsoil, I found myself using these methods to stop hillside erosion.
When dealing with slopes of 30° or less, shredded bark will outperform gravel. The fibers interlock with each other, creating a stable surface. Rainwater flows through slowly. Gravel eventually slips down slope and creates piles. Bark remains flat tree season after season. My 25-degree slope withstood the spring storms.
Shredded Bark
- Best For: Slopes under 30°
- Installation: Apply 3-4 inch layer
- Erosion Control: 85% runoff reduction
- Lifespan: 2-3 years before refresh
- Cost: $0.20 per square foot
Coconut Coir Mats
- Best For: Slopes 30°-45°
- Installation: Roll out and stake every 3 feet
- Erosion Control: 95% runoff reduction
- Lifespan: 5-7 years biodegradable
- Cost: $1.50 per square foot
Jute Netting System
- Best For: Slopes over 45°
- Installation: Layer over gravel base with U-pins
- Erosion Control: 98% runoff reduction
- Lifespan: 2 years before replacement
- Cost: $2.00 per square foot
Proper installation of coconut coir mats will yield the best results. Roll the mats downhill, overlapping the edges by 6 inches. Place 12-inch landscape stakes every 3 feet. Plant grasses for erosion control in the mesh. This acts as a living barrier that strengthens and improves over time - my slope completed its transformation in one growing season!
Common Slope Mulch Mistakes. Not using smooth gravel by itself. It is a landslide waiting to happen in a storm. Straw and wood chips can wash away. Always prep the slope first. Remove the loose debris. Create small terraces as needed. Water the area before applying the mulch.
Read the full article: Top 10 Best Mulch for Gardens: Ultimate Guide
