protein, the carob’s pods can be milled to a fine powder for use as a chocolate substitute. Within the pods, the carob seeds are of remarkably uniform weight, and ancient Mediterranean civilizations used them as a unit of measure to weigh gems and other precious substances (the Arabic word for the carob seed was quirat , from which our word carat originates). You will rarely see the pods or seeds of the carob in San Francisco, because only female trees produce them (11 months after pollination), and the females are seldom planted on city streets.
LOCATION: Northeast corner of 22nd and Dolores Sts. (on Dolores) in the Mission; also at 850 Florida St./20th St. in the Mission and at 957 Cole St./Parnassus Ave. in Cole Valley
Female seedpod
The carob is a native of the eastern Mediterranean. It grows to 30 feet, with a dense, rounded crown. This is a tree to plant for its foliage. The glossy, dark green leaves are beautiful and distinctive, with each compound leaf divided into 4–10 round leaflets. Small, inconspicuous red flowers form in spring. Not surprisingly, given its desert origin, the carob is very drought tolerant. A drawback: Carobs have extremely invasive roots, and mature trees will cause significant sidewalk damage.
Our Wild Parrots and Their Chosen Trees
AMONG San Francisco’s quirky charms is a flock of wild parrots—estimated at more than 200 birds. The parrots roost in Sue Bierman Park, formerly called Ferry Park, near the Embarcadero. The birds are red-masked conures, native to Ecuador and Peru, and are the offspring of pets that escaped in the late 1980s and early 1990s. With brilliant green bodies and red heads, they have become something of a tourist attraction in San Francisco.
The parrots make Sue Bierman Park their home because of its tall Lombardy poplars (Populus nigra ‘Italica’). These trees offer good perches, with great visibility—helping the parrots watch for hawks, their most common predator. During breeding season, the birds like to nest in Canary Island date palm trees (Phoenix canariensis). When this palm’s fronds break off the trunk, a small hole or indentation is often created. With a little industrious digging, the parrots can turn these spots into perfect nesting holes.
During most of the year, the flock rarely leaves the city’s northeast quadrant, an area ranging from the Ferry Building environs to Telegraph Hill, Russian Hill, North Beach, Fort Mason, and the eastern edge of the Presidio. But as tree fruits begin to ripen in less dense parts of the city during the summer and fall, the parrots make an annual trek to the Castro, Cole Valley, and other neighborhoods to the south and west. They seem to know exactly when and where to visit.
During summer months, plum trees on the streets and in the backyards of these neighborhoods beckon the parrots. Even though the city discourages planting fruit-bearing trees on the streets, in July and August many backyard specimens fill with ripe plums—irresistible to the parrots. They perch in the trees, methodically grabbing the fruit and eating it from the tight grasp of their claws. Another parrot favorite is the English hawthorn tree (Crataegus laevigata), whose fruit also ripens in July and August.
At our home in Parnassus Heights, we have a backyard pippin apple tree (Malus domestica), and we know that, come October, we have to harvest it before the parrots do. They have figured out exactly when the apples ripen, so we count on their annual fall visits, when they strip the tree of the apples we can’t reach.
The parrots typically travel in large flocks, and they’re very loud, so if they stop by your neighborhood, they’ll be hard to miss. If you really want a visit, bribe them by planting a plum, hawthorn, or apple tree. It may take a few years, but eventually you’ll be able to match your flora with some of San Francisco’s most colorful fauna.
Lyonothamnus floribundus ssp. asplenifolius
CATALINA IRONWOOD
LOCATION: 641 Broderick St./Fulton St. in NOPA; also 15 Hermann St./Market St. in Upper Market
The Catalina ironwood is one of the few California native trees planted on San Francisco streets. Although fossil records prove that this tree was once widespread throughout California, it is now limited in the wild to the Channel Islands of Santa Catalina, and to Santa Cruz, Santa Rosa, and San Clemente off the Southern California coast. This tree demonstrates how islands often develop unique flora as environmental threats from the mainland (in this case, perhaps plant-eating animals) are stopped at water’s edge.
Catalina ironwood was first discovered in 1884 by William Lyon and named in his honor, as you can see from its scientific name, but it was pioneering nurseryman Francisco Franceschi who introduced this tree into the nursery trade. Upon finding that the tree was difficult to germinate from seed or branch cuttings, he set out to the Channel Islands to collect a full-grown specimen with large enough roots to permit root cuttings. Suspected as an outlaw by the Coast Guard, he was fired upon until his vessel began to leak. Furiously bailing water, he managed to reach Santa Barbara Harbor with his prize in hand. Young plants from this specimen were introduced to nurseries a few years later. Ironically, today this tree is planted worldwide, but is threatened in its native habitat of the Channel Islands as a result of grazing by introduced feral goats.
In addition to its interesting history, this tree has a distinctive appearance, with deep green, glossy leaves divided into three to seven leaflets. Each leaflet is deeply notched, giving a fernlike grace to the entire tree. The bark is reddish brown and peels into narrow vertical strips. In May and June, the tree produces small white blossoms that occur in large flat clusters 3–6 inches wide.
Ulmus parvifolia
CHINESE ELM
LOCATION: 245–255 Hartford St./19th St. in the Castro; many examples on both sides of Folsom St. between 24th and 26th Sts. in the Mission
The Chinese elm is by far the most common elm on San Francisco streets. A medium- to large-sized tree (growing to 30–35 feet), it keeps its leaves year-round in San Francisco’s mild climate and develops an attractive weeping form as it matures. The 1- to 2-inch leaves are smaller than those on other urban elms; this elm is also distinguished by bark that sheds in patches, creating beautiful two-toned (gray and brown) mottled patterns. Chinese elms are resistant to Dutch elm disease, which has decimated the American elm in most of the United States. San Francisco elms have not yet been affected by Dutch elm disease, and you can still find American elms here and there in the city. The Chinese elm is native to northern China, Japan, and Korea.
Sequoia sempervirens
COAST REDWOOD
LOCATION: Redwood Park on the east side of the Transamerica Pyramid in the Financial District. Muir Woods in Marin County is the best spot nearby to see coast redwoods in their
