For the rest of us? Enter Plant*SF, a non-profit dedicated to promoting "permeable landscaping equally as sustainable urban infrastructural practice and as a beautification effort." After reading through their site and looking at the projects they've worked on, we think everyone should work with Plant*SF.
Don't have a sidewalk that meets requirements for greening? Donate time or money to beautify the rest of Noe Valley.
Bonus: Plant*SF is also pushing for alternatives to the water- and maintenance-intensive hanging flower baskets like we have on 24th St:
Planted hanging baskets are gaining popularity in San Francisco and while beautiful, daily watering and use of 'disposable' plants keeps them far from being sustainable. Plant*SF has proposed climate adapted, self-propogating alternatives that will be piloted in front of City Hall soon.[Plant*SF]