Erosion Control Blankets & Hydromulch in Denver, CO

Erosion control blankets and hydromulch are what we use in Denver when seed alone will not stay put: a cut slope behind a new house, a swale that carries the whole subdivision's runoff, a channel bank, or a hillside on the west side of the metro where the ground rises toward the foothills. These erosion control services cover the soil immediately, slow the water down and keep the seed in place long enough to grow.

Why Denver slopes wash out

Denver's dry months are not the problem. The trouble comes from April through August, when the area gets most of its precipitation, and much of it arrives as heavy afternoon thunderstorms, sometimes with hail. Rain falling hard on bare, compacted soil does not soak in; it sheets off and carries soil with it, cutting rills that grow into gullies with each storm. A slope seeded in May with nothing on it can be scoured to bare subsoil by July.

Choosing the cover

The right product depends on the slope, how much water crosses it and how long it needs to last.

• Standard hydromulch: wood fiber mulch sprayed with the seed. Fine for gentle slopes and flat ground.
• Heavier hydromulch with tackifier: more mulch per acre for moderate slopes and wind-exposed sites.
• Bonded fiber matrix (BFM): a hydraulically applied mulch that bonds into a continuous layer, used on steeper slopes where blankets are hard to anchor or rock makes stapling difficult.
• Straw blankets: straw stitched into netting, rolled out and stapled. A common choice for slopes and swales.
• Straw and coconut (coir) blankets: longer lasting, for steeper slopes and channels that see real flow.
• Coir blankets: the longest-lasting natural option for channels and banks that need protection for more than one season.

Installing a blanket correctly

Most blanket failures come from installation, not the product. The soil is graded smooth and seeded first, the top of the blanket is buried in a trench at the crest of the slope, rolls run down the slope rather than across it, edges overlap shingle-style so water cannot get underneath, and staples go in at the pattern the manufacturer calls for. In a channel, the blanket is laid in the direction of flow with check slots across it. Skipping any of those steps is how a blanket ends up in a pile at the bottom of the slope.

Native seed on slopes

On non-irrigated slopes we usually recommend a native dryland mix. Blue grama is the main native grass on plains soils like the USDA's Ascalon series, and CSU Extension lists buffalograss and blue grama as grasses that work for Colorado lawns. Once established, they take far less water than bluegrass, which matters on a slope where irrigation runs off before it soaks in.

Swelling clay and slopes

Many Front Range slopes are cut into clay. The Colorado Geological Survey describes expansive clays that swell when wet and crack when dry, leaving open desiccation cracks at the surface. Those cracks channel water into a slope. A continuous cover of mulch or blanket, followed by roots, keeps the surface from cycling as hard.