RMNOTES VERTICAL MULCH 1 BAINBRIDGE 1995 Vertical mulch for site protection and revegetation 1995 Restoration and Management Notes 14(1):72 David A. Bainbridge Environmental Studies US International University 10455 Pomerado Road San Diego, CA 92131 Erosion control and revegetation of bare slopes and large barren areas caused by construction, vehicle operation, or recreational activities can be difficult and expensive. Mechanical treatments are expensive, leave potentially permanent patterns on the landscape, and are ill-suited for restoration and protection of natural areas. Vertical mulching, or placing straw, sticks, or brush upright in the soil can be effective for treating these problem areas, figure 1,2. Vertical mulch can: slow water movement; providing open channels for water penetration into the deep soil; protect safe sites for seeds to catch and sprout; serve as a wind break to trap seeds and dust; offer shade and cover for seedlings; and provide a source of below-ground organic matter to help return the soil ecosystem to health. Several materials can be used for vertical mulch, including: broom corn, straw, brush and reeds. The best choice for a given site will depend on availability and cost of materials, project demand for aesthetics, integration of seeding and container planting, and severity of erosion and land stability problems. 2. Options Broom corn (Sorghum vulgare) is a promising vertical mulch. The stem is easily inserted into a hole or slot in the ground (drilled, punched, or dug) and the multi- branched top is an effective wind break and erosion trap. Overall lengths range from 18-24 inches. The plants are harvested in flower (Kirby, 1963) and are further processed to eliminate immature seeds, so the material is clean and unlikely to have viable seeds. It is more expensive than straw, but the fraction of broom corn that doesn't meet broom specifications could be reasonably inexpensive if a revegetation market is developed. Several people are needed for an effective installation team. Punches, shovels, or drills are used to make placement holes or slots. Broom corn has worked well for wind erosion control and improving soil moisture at Red Rock Canyon State Park (Bainbridge, 1995), figure 3. Broom corn was placed into holes made with a soil punch or large screwdriver. The broom corn is holding up well despite the rains of early 1995. The broom corn looks very much like dead native plants and appears likely to last for several years. A 100 pound bale should treat 2-4 acres with 1000 stalks per acre. A bale would also create 60-70 2 foot wide check dams. Cost are expected to run about $50/acre for material and $50- 150/acre for labor.