The goal of these landscape guidelines is to develop landscape continuity for regional roadway corridors based on the natural landscape character and complimentary to urban development. The following best management practices can provide consistency between public agencies for roadways and public lands within private development during planning and construction phases.
- Seek to maximize preservation of native vegetation on public and private lands along the roadway corridors. Grading of roadway, parking, and building pads will level the topography to achieve a project development program. To preserve the visual landscape identity along the public roadways, a minimum width (50’ wide) of existing coast live oak or chaparral vegetation should be preserved.
- To preserve roadway vegetation, incorporate low retaining walls at select locations, maximize cut slopes where necessary, incorporate grade separations in the median, or grade separation of trails and sidewalks to reduce the extent of tree/vegetation removal for roadway grading.
- Protection of tree/vegetation on private lands through grading design and retaining walls is recommended to enhance the character of roadway corridors.
- Native coastal topsoils are typically stripped and buried as fill material during the grading process in the construction phase. When feasible during grading, strip the 6” – 12” top layer of site soils and stockpile for reuse in medians, planting strips and earth shoulders of roadway projects. This will retain natural soil nutrients and drainage quality more suitable for native plant establishment. Where native topsoils are not stockpiled for reuse, obtain a horticultural soils test for soil amendment recommendations suitable for proposed planting design.
- Town & Village Centers have limited right-of-way planting areas with buildings located at the back of sidewalk. Traditional street tree planting at 25’ – 35’ spacing is appropriate. In most all other locations, trees should be planted at random spacing and where possible in groves/clusters. Tree mitigation planting on roadways should be small container sizes. Tree planting should only be allowed in medians 8’ wide or greater, at random spacing clustered in groves.
- Where planting in the roadway right-of-way outside Town & Village Centers, use one and five gallon container sizes to allow nursery grown material to acclimate with site conditions. Provide wind screen for container plantings 1 gallon and larger.
- To encourage native plants utilization in new development projects, approval agencies should consider a percentage (80% native plants) along adjacent roadway right-of-way as a permit condition. Cities should support developers in exploring creative ways to integrate native plant design and establishment, and maintenance into roadway corridors.
- As part of the roadway right-of-way construction where installation of native grasses, shrubs and trees are proposed, require installation be scheduled for the winter season with a one year growing season maintenance obligation.
- Where container plants are used for installation, require an underground irrigation system, with a 1-year/80% survival rate permit condition; if not, a 3-year establishment agreement with an 80% survival rate should be a permit condition.