PROPAGATION AND CULTURE OF NEW SPECIES OF DROUGHT-TOLERANT PLANTS FOR HIGHWAYS

This report contains findings of a research project which was carried out from January 1973 to June 30, 1975. The primary objective of the project was to find and introduce a much wider array of drought tolerant-low maintenance, native and exotic trees, shrubs and ground covers. These plants are specifically intended for highways in those areas of California that are characterized by mediterranean climate. Ninety-two cultivated but rarely or never introduced species (including a few that are shade tolerant) were evaluated on site and selected on the basis of several criteria. Techniques for vegetative propagation of the majority of these species by means of leafy stem cuttings were worked out. Seeds of 127 species which were obtained through the University of California at Davis (UCD) Arboretum seed exchange program or collected in the field were germinated. Plantings of these seedlings in the UCD Arboretum and selected sites by the California Department of Transportation should prove their feasibility in the future.