|Photo credit - Doug Richardson|
Wednesday, October 5, 2011
Doug Richardson (a landscaper who uses vetiver and native plants in landscape design) planted the slope in the photo above at the Santa Barbara City College (California) some years ago. Before Vetiver was planted there was mud and rock in the street after every major storm. There have been no problems since.
Native plants have voluntarily established themselves. The image shows this slope protected with vetiver, along with the volunteer trees and shrubs that include: the tree - Toyon (Heteromeles arbutifolia). Also you can also make out a number of smaller shrubs native to this area including Coastal Sage (Artemesia californica), and Chaparral Broom (Baccharis pilularis) both of which are growing well with the Vetiver. The native Blackberry is also growing with the Vetiver but is harder to see in these photos.
Doug (who was Chairman of the Environmental Horticulture Department at Santa Barbara City College) says that experience in California is that after a season of irrigation to establish Vetiver no further irrigation is required to assure its survival. Fires are a serious problem in California. He has found that Vetiver outperforms the native grass Leymus Condensatus in maintaining green less flammable foliage in drought conditions. This does not mean that vetiver does not burn once ignited, but it produces flames that are about 6 to 8 ft high, compared to native chaparral species (like most of the Sages) which can be quick to ignite, burn at higher temperatures, throw flames 50'-100' in height (Ceanothus, Manzanita, Adenostoma, etc.) and throw embers which are large and persistent. Vetiver, as a grass with high moisture content, has less actual biomass and density than the woodier species. Vetiver sprouts quickly from its roots if burned, and this is a huge plus for subsequent erosion control not to mention the preservation of the original costs and investment that went to getting it established. If the Vetiver was used for decontaminating soils, such as a landfill, containing leachates and effluent it would be lush and green and unlikely to be flammable. Interestingly in Fiji, where vetiver (for erosion control) was grown in association with sugar cane, appeared to be only singed when the cane was burned prior to harvesting
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Useful gallery of all blog images (with captions) posted on Picassa