It's a nuance not without its risk of controversy, as SF Citizen expressed in a recent post. The movement to add more landscaping to San Francisco streets has been gaining steam and literally gaining ground in the last few years. It think this is a good thing for a lot of reasons. But almost all of the square footage that's been de-paved and planted has been taken from our pedestrian space, and that's a distinctly bad thing.
Instead, we could plant trees in the road, or we could green a street as part of a more comprehensive repurposing of the space.
For example, the redesign of Newcomb Avenue in the Bayview is being heralded as a "sustainable streetscape model," but the amount of car space seems to remain the same and the sidewalks are significantly narrowed to accommodate planting beds. To be clear, we're not talking about a narrow street with barely any space for moving vehicles, Newcomb Ave has ample room for wide traffic lanes and perpendicular parking - an above-average asphalt width for a residential street. But none of that was given up for greening, instead the sidewalks will shrink.
Another unscientifically-selected example that has come across my radar recently is a plan to landscape Turk Boulevard at Lyon St. To be fair, it's unclear from this website what the specific details of the final plan are, but one photo in particular strikes me as a bad sign:
One other questionable greening practice that seems to be picking up speed under its own momentum is the center median. I'm not a fan of medians. In those rare cases when the city family actually decides to remove some road space from the sole use of the private car it seems to be given exclusively to plants that nobody is allowed to get close to, and that are far from the gutters where they'd absorb some rainwater. Take this very unspecific plan to give Bryant Street a road diet at Cesar Chavez, part of the Mission Streetscape Plan:
I'd like to take a moment again to be very clear: I support increased landscaping as part of the streetscape of San Francisco. I support more permeable surfaces to help with the problems runoff can present during storms. But I know that the pedestrian realm, and the flexibility of the space we reserve for pedestrians, is vitally important to the success of our streets as public spaces. Well-designed green streets will make more room for its greenest uses, not less.