This article is a great example of why native plants species are so important for wetlands and dry chaparral plant communities like we have in Ojai.
Root Systems of Prairie Plants http://www.il.nrcs.usda.gov/technical/plants/npg/NPG-rootsystems.html
The fundamental basis for encouraging use of native plant species for improved soil erosion control in streams and
stormwater facilities lies in the fact that native plants have extensive root systems which improve the ability of the soil to
infiltrate water and withstand wet or erosive conditions. Native plant species, like those listed in this Guide, often have greater
biomass below the surface. In this illustration, note the Kentucky Bluegrass shown on the far left, which, when compared to native
grass and forb species, exhibits a shallow root system. Illustration provided by Heidi Natura of the Conservation Research