Here on the 20th Street Corridor, our plant life is continuously cared for with love and patience. The lush greens and beautiful flowers you see along the sidewalks which attract and feed the creatures of the Mission are grown by Ellyn Shea, an esteemed gardener and consultant of San Francisco. We were lucky today to get the exclusive scoop from Ellyn about the current plant life along the corridor.
California Wild Lilac: Born to Laugh at Drought
When I arrived in the morning to take care of the garden on 20th Street recently, I heard the chirping of birds but didn’t see any around. Soon, I realized that they were all inside a flowered shrub, known as California Wild Lilac (Ceanothus). This purpled plant forms a dense green wall in front of our favorite neighborhood bar, Trick Dog. Birds appreciate a good hiding place where they feel safe, and Wild Lilac provides the best shelter on the block. Bees also often take well to the lilac as it provides nectar and pollen for them to feed. The common name refers more to the shape of the flowers than the smell, although the flowers (mostly blue, but sometimes white) do have a light pleasant fragrance. Bees also love this plant.
Ceanothus (see-uh-no-thus) is a member of the Buckthorn family (Rhamnaceae), of which the most famous member is the Chinese jujube tree. Not to be confused with the jujube candy, the trees produces a fruit more like a date. Ceanothus berries are not eaten today by humans, although the Native Americans supposedly once used the leaves and/or flowers to make tea. About 50-60 species of Ceanothus can be found in America, mostly in California. Some can even be seen in Eastern North America and even as far south as Guatemala. Ceanothus can actually convert nitrogen from the air into soil nitrogen, a necessary plant nutrient. This trick, known as “nitrogen fixing,” allows Ceanothus species to grow in nutrient-poor soils. Who would have guessed that this small shrub could be so useful to the everyday needs of its surroundings?
Our Ceanothus, also known as Blueblossom (C. thyrsiflorus) has the potential to get 8 feet tall and 12 feet wide! Since it is in a sidewalk garden, we have to keep it pruned to maintain a smaller size, keeping it safetly out of the street and sidewalk. Unfortunately, the flowers emerge on the branch tips making it harder to see them. So, for the best flower display, look on the top or sides of the hedge to catch a whiff of fragrance. Luckily, the shrub in front of Northern Exposure is smaller and hasn’t needed to be pruned much, so it has bloomed the most flowers.
California Tortoiseshell (by Walter Siegmund via Wikimedia Commons)
Even without flowers, this shrub has a lot to offer local wildlife. In addition to providing shelter for birds, the leaves provide food for the larvae (caterpillars) of the California Tortoiseshell butterfly. This special critter is one of only 36 butterfly species native to San Francisco. Butterfly mothers are typically very picky about where they lay their eggs – Ceanothus is a host plant for several other butterfly species outside the city.
Blueblossom Ceanothus may be a little large for your garden, but there are many other kinds of Ceanothus to fit any space, from a small tree to a prostrate ground cover. Some even have variegated leaves , such as the one shown above, the low-growing Ceanothus ‘Diamond Heights.’ To find out more about growing your own, check out the book California Native Plants for the Garden (Carol Bornstein, David Fross and Bart O’Brien). Whichever one you plant, make sure there is plenty of sun, good drainage, and little to no water in the summer. No need to fertilize – they’re nitrogen-fixers!
Ceanothus has a reputation for being a “short-lived” plant. In many cases, improper watering or site selection is actually the cause of this. In nature, California Ceanothus are known as the “pioneer” species after a fire. Surprisingly, their seeds actually require fire to grow, and the plant is the first to colonize a burned area. After 15 to 20 years, plants decline as other species fill in. However, in a garden setting under ideal conditions, Ceanothus could live 25 years or more. During this extended drought, Ceanothus is just what the doctor ordered for our gardens.
Now that we have learned so much about what populates our sidewalks, take a look next time you’re strolling through the corridor. Thank you Ellyn Shea for teaching us and cherishing the corridors nature! For more tips on gardening, visit Ellyn at www.garden-guidance.com.