Street Plants of San Francisco

By: Rida Jan

Despite San Francisco’s dense population and development, its rich biodiversity and wildlife provide great value to the city’s ecosystem and environment. This blog examines a few of the many unique plant species found in my neighborhood.

The species Euryops chrysanthemoides is a small herbaceous shrub part of the Asteraceae, or daisy, family commonly known by the names “African bush daisy” and “bull’s eye.” It is not native to California, rather to Southern Africa such as in the Eastern Cape and Swaziland, and is additionally grown in tropical and subtropical regions around the world as a horticultural/ornamental plant.

This daisy is typically found on forest edges, and in coastal scrubs, grasslands, disturbed areas, riverine bushes, and ravines. Although it is present as an invasive weed in some areas such as South Wales, it is not known to be invasive in other places such as California where it has cultivated and naturalized.

This perennial plant grows year-round and thrives in dry, full-sun conditions. The bright yellow color of these flowers attract butterflies as well as other pollen and nectar-feeding insects, and its seeds are eaten by birds.

The Pleroma urvilleanum is an ornamental flowering plant of the family Melastomataceae, and goes by many common names that depict the delicate appearance of this flower, such as “princess flower,” “glory bush,” and “purple glory tree.” This species is native to Brazil, but is not known to be invasive to California and other states.

This princess flower can grow as an evergreen shrub and as a small tree ranging anywhere from 10 to 20 feet in height. Some of these flowers are open all year, but are especially foun in abundance from spring to winter.

Round and dry brown fruits are produced by these plants, but this typically does not attract any wildlife. The growth of these flowers are enhanced by full sun and moist, well-drained soil.

The Rosaceae family hosts many different species such as the one shown above, Rosa spithamaea, more commonly known as the ground rose. It grows as a small perennial shrub native to California and Oregon, flowering mostly during the spring and summer especially during April to July. These ornamental plants are typically pink in color, but can turn bright red during the fall. It is found to grow primarily in forest and chaparral habitats, especially in recently burned areas.

The structure and material of the ground rose allows great usage for surrounding wildlife. Its dense thickets give protection and nesting shelter for birds, mammals, and bees. Cavity-nesting bees are able to nest in its small hollow stems, and leafcutter bees collect leaf material for their nests. The brightly colored flowers attract native bees and other insects as a source for pollen. It also serves as a food source for rabbits, mice, fruit-eating birds, butterflies, bees, and moths via its rose hips (accessory fruit) and larva.

The ground rose can provide many medicinal benefits to humans. The infusion of the petals and buds may be used as an eyewash and fever treatment in infants, and the infusion of the leaves may be used for intestinal illnesses. The extracted material from the rose hips are a source of Vitamin C, and have been used to treat colds, fevers, indigestion, arthritis, and kidney illnesses. Interestingly, this material can also be used to make oils, teas, wines, and jams.

The oxeye daisy, dog daisy, or marguerite, specifically the Leucanthemum vulgare in the Asteraceae or daisy family, is native to Europe and temperate regions of Asia and was later introduced to North America, Australia, and New Zealand introduced via seed mixes and as an ornamental plant. This perennial herb flowers primarily from May to October. It typically thrives in temperate regions where soils are heavy and damp.

It is known to be invasive in more than forty countries, such as North America, found as weeds on degraded pastures and roadsides and forms dense thickets that cause natural habitat loss. The plant tends to carry several crop diseases, and thus cows that eat it, which is rare, in pastures may produce milk with undesirable flavors. These flowers attract various insects for pollen and nectar, such as bees, beetles, ants, and moths.

Consumption of these flowers occurs in some parts of the world, such as for herbal teas through picking and drying the flowers, and as a seasoning similar to capers through marinating the unopened flower buds. Allergies to these flowers can also occur and cause contact dermatitis.

One of the most popular species of the Genus Ceanothus is the blueblossom, specifically the Ceanothus thyrsiflorus. It is native to northern, central, and southern California blooming perennially in the winter or spring. Its size is various, being able to grow anywhere from 2 feet to 30 feet tall. Its leaves range from bright green to dark green, and its flowers are white, light blue, dark blue, or purple.

This species prefers various sun exposure based on the climate they are inhabited in. In areas with higher temperature, northern slopes, and naturally moist areas, it prefers more shade, while in cooler coastal areas, it prefers more sun and can tolerate drier conditions.

Birds and mammals utilize its seed pods as a food source, and its flowers attract hummingbirds, bees, and butterflies. This plant can produce effective and gentle soaps if crushed with water, and Native Americans have utilized it for their ceremonial wreaths.

The Persian Cyclamen, or the Cyclamen persicum, belongs to the Primulaceae or primrose family. These ornamental flowers are a perennial plant, blooming from the winter to spring or in autumn. The high temperatures and dryness during the summer months lead to intolerance and death of the plants.

They are not native to California, but rather native in the Mediterranean such as Turkey, Lebanon, Syria, and Palestine, and were known to be introduced by monks in Algeria, Tunisia, and on a few Greek islands. They are also natively grown on rocky hillsides, shrubland, and woodland, and are not known to be invasive.

Their unique flowers capture the eye with their heart-shaped leaves, typically of white to pale pink and deep pink to magenta. Although these flowers are naturally sweetly scented, cultivated forms have caused this scent to be lost. In certain cultures, the semi-poisonous dark brown tuberous roots can be used to make soap or cause fish to rise to the poison-sprinkled surfaces of water and be collected by fishermen. They are often pollinated by small months, thrips, and bees.

On September 17, 2022, I volunteered at the National AIDS Memorial Grove in Golden Gate Park. I worked with other volunteers to remove invasive blackberry species which can form dense bushes that invade many open areas, prevent beneficial species from growing, and cause natural habitat loss. After my group shoveled out these invasive plants, a new group of volunteers came and planted a tree in that newly opened space. It was wonderful to be a part of this process and contribute to the great beauty of this park. I was able to see firsthand how humans and wildlife can work together to help one another thrive.