Native plant restoration along highway rights-of-way in California

The establishment of native perennial grasses along highway rights-of-way provides benefits of reduced weed infestations and herbicide use and increased sediment control and plant species diversity.  Cultural and chemical management techniques are necessary to improve establishment success of native perennial grasses in the first two to five years after planting.  Field studies were conducted along two roadway environments in northern California to determine the effect of 1) burning, spraying, cultivating and species selection on the establishment of native perennial grasses and persistence of non-native annual vegetation and 2) mowing, burning or spraying alone and in combination on an existing stand of native perennial grasses with dense populations of non-native annual species, particularly yellow starthistle.  In the I-5 median, burning and spraying had the most significant effect on native grass establishment and reducing non-native vegetation persistence.  Cultivation and species selection (wet or dry site seed mix) had no significant effect on native perennial grass establishment or annual weed persistence at this site.  Along Highway 20 in Colusa County, native perennial grass stands that were overrun with non-native annual species, particularly yellow starthistle, were effectively treated with a combination of well-timed vegetation control techniques.