This is a companion piece to A Parkway in Progress: The Seismic Remake of Doyle Drive Shapes Up
In a small, temperature-controlled greenhouse in the Fort Scott District of the Presidio in San Francisco, barely-visible blades of blue-eyed grass and bits of young coyote bush plants are beginning to peak out of soil. It doesn’t look like much yet, but the closely monitored greenery will eventually become part of the lush landscaping at the Presidio Parkway, the major seismic remake of the Doyle Drive approach to the Golden Gate Bridge.
Blue-eyed grass and coyote bush are among the many native plant species that will be incorporated into the project’s landscaping – and among the 62,000 native plants currently growing at the Presidio Nursery for projects across the park.
“Native” in this case is not used loosely. The 1,500-acre Presidio is home to 12 different native plants communities found throughout five subwatersheds, said Brianna Schaefer, nursery manager. Doyle Drive itself goes through two separate subwatersheds, so landscapers and ecologists had to carefully determine which species would be appropriate for which areas.
“We wanted to make sure we weren’t bringing in anything new that would change that genetic landscape,” Schaefer said. Inbreeding between different plant populations can affect the health of the restored area.
Project managers working in the Presidio must request plants from the nursery a year and a half ahead of time. Once the nursery staff determines the feasibility of a request, they collect seeds from the park, clean and dry them in a dehydrator, and store them in a refrigerator, where they are organized based on their species and subwatersheds. Staff must keep a close eye on growing calendars to figure out when to remove a seed from the refrigerator for planting.
Mimicking Mother Nature
“We’re trying to mimic Mother Nature in here,” said Schaefer, who gave the example of a wetland plant, whose seed flat is soaked in water to simulate its natural environment and induce germination. The nursery generally does not irrigate the plantings in the field, relying instead on the winter rains.
“Everything grown here gets collected in the park, propagated from the plants in the park, and put back in the park,” said Mark Helmbrecht, Transportation Program Manager at the Presidio Trust. Together, the Trust, the National Park Service and Golden Gate National Parks Conservancy run the nursery, which opened in 1995.
The Presidio Nursery is a collection of facilities: a new colorful, high-tech seed lab; a shade house; a glasshouse; and a volunteer center. Each year, the nursery collects about 300 native plant species — and there’s demand for even more
“You can only have so many projects a year that need native plants,” Helmbrecht said.
The nursery staff often has to modify the project managers’ requests, due to capacity, seed availability and park policy. In the case of a large project like the Presidio Parkway, landscapers might ask the nursery for 15,000 of one plant that the Presidio may only grow 800 of each year, Schaefer said.
“We had to choose things that we had an abundance of,” Schaefer said. “In a park that’s very fragmented like the Presidio, a lot of our native plant populations are pretty small. One of the things we’re trying to do here is not take too much out from the wild, so we have a strict collection protocol we adhere to here.” The nursery workers will only collect 5 percent of a given population, compared to their counterparts at places like the Marin Headlands nursery, where larger amounts can be collected from the more ecologically-consistent acres.
Discovering the Franciscan Manzanita
The native plants propagating for the Parkway include the Coyote Bush, a tall evergreen shrub that serves as a habitat for 300 animal species. There is also an edible red-flowering currant plant, whose “beautiful sprays of little pink flowers attract hummingbirds,” Schaefer said. There will be 1,600 low-growing blue-eyed grass plants, which produce small purple flowers, and 21 native coast live oak trees. The native Douglas irises growing in the nursery’s greenhouse will also go to Doyle. In total, the native and outside landscaped plants at the Presidio Parkway will number 114,000.
One native plant that will not be featured in the new Doyle design is the Franciscan manzanita. The shrub, thought to be extinct for decades, was discovered in 2009 in a landlocked area in the middle of the soon-to-be-bulldozed highway. The original plant is hidden in a secret location, but its cuttings are growing at a handful of nurseries throughout the Bay Area. As for potential Presidio plantings, Schaefer said U.S. Fish and Wildlife Service regulates where the endangered species can be planted.
The park staff is still in awe of the discovery, which was made by a botanist who was driving on the highway and noticed the shrub where some trees had been removed.
“It’s pretty amazing to discover a species that you thought was extinct in the wild on a median strip on a highway,” Schaefer said.
While tending to the plants, the small nursery staff — three people and a few interns throughout the year — also host educational and youth programs, and oversee hundreds of volunteers.
Even when years pass by without the discovery of an extinct species, the staff get a thrill from the work they do.
“If I get to play with the plants and hang out with volunteers, that’s a good day,” Schaefer said.
To visit the Presidio Nursery, contact staff at (415) 561-4826. Volunteer drop-in hours are Wednesday and Saturday 1-4 p.m. The nursery is located at 1249 Appleton St, San Francisco, CA 94129.