Drainage Design Manual - the City of San Luis Obispo

Placement of weed control fabric or matting can significantly improve thesurvival of revegetation plants, and should be required where competition fromweeds is anticipated. A .9 x .9 meter (3' x 3') mat should be placed around eachplant. The mat can be secured to the ground with 152-millimeter (6-inch), U-shaped staples.• Planting Container StockPlanting holes for larger container planting stock should be at least two times aslarge in diameter as the container and one and one-half times as deep. The rootball of container plants should be set at 25.4-millimeter (1-inch) above finishgrade. Backfill soil should be tamped solidly around the roots. After holes havebeen backfilled 2/3 full, the plant should be thoroughly watered to settle the soiland insure good soil/root contact before placing the remainder of the planting soil.A slow release fertilizer (i.e., agriform tablets or Osmocote granules) should beplaced around the root ball per the manufacturer’s specifications. A wateringbasin should be constructed around each plant by forming a 101-millimeters (4-inch) high circular berm 304 millimeters (12 inches) from the edge of the rootball. All plants should be watered immediately after planting. A .9 x .9 meter (3'x 3') weed control fabric mat should be placed and securely fastened to the groundaround each plant.• Planting Cuttings and PolesWillows cuttings and cottonwood poles can be planted at a relatively low cost onmany revegetation projects. Willow cuttings should be approximately 609 to 914mm (24 to 36 inches) long and a minimum of 12 millimeters (½-inch) in diameter.Cottonwood poles up to 2 meters (6.6 ft.) in length can be installed in pre-drilledholes, and backfilled with the native soil. Pilot holes for willow cuttings can bemade by driving a steel stake into the ground to a depth of 203 mm. (8inches) ormore. Cuttings can be planted by inserting them into the pilot holes and foottampingsoil around them. In soft, moist soils, willow cuttings can be pushed intothe soil or hammered down with a rubber mallet. No more than 106 to 152 mm (4to 6 inches) of a cutting should be exposed at the surface of the soil. Willowcuttings can be planted densely .9 to 1.2 meters (3 to 4 feet on center) to helpstabilize banks and prevent erosion. Cottonwood poles should be at least 1.5meters (5 feet) long with a diagonally cut base at least 51 mm (2 inches) indiameter and a top at least 5/8-inch in diameter. Poles should be taken andplanted during the dormant season (December/January). Prune off all sidebranches and insert poles in a augured hole to a depth of approximately two-thirdsof their length. All poles must be planted with the buds pointing up. Bestsprouting results occur when plant materials are installed on site within eighthours of cutting. They can be kept fresh at the job site by placing them in thestreambed. Alternatively, provisions for proper storage should be made.Materials should be fresh, dormant and non-desiccated when installed.SLO Creek Drainage Design Manual 154 February 2003