Wildflower Walk Reveals Complicated History of Half Moon Bay Coastal Bluffs

Wildflowers and history combined on Saturday when local botanist and author Toni Corelli spoke at a workshop on plant identification and then led a plant walk along the railroad right-of-way, paralleling Railroad Avenue, and the coastal bluff west of the right-of-way.  The event was sponsored by the Coastside Land Trust (CLT), a nonprofit created in 1997, originally with the purpose of preserving the railroad right-of-way and protecting it from development.

The right-of-way is a reminder that the Ocean Shore Railroad once ran from San Francisco to the Coastside.  In the first two decades of the 20th century it brought passengers and commerce to the sparsely populated coast.  The railroad went bankrupt in 1920, but it left behind a legacy—the right-of-way for the tracks themselves and plots of land adjacent to the tracks.

CLT Executive Director Jo Chamberlain explained that in the early 1900s the government offered free land to railroad companies—a mile of land for every mile of track they laid.  The Ocean Shore Railroad subdivided land along the track in Half Moon Bay into small parcels and sold them. 

In 1997, when a developer wanted to build condos along the railroad right-of-way, a group of citizens formed what was to become the Coastside Land Trust to help the city of Half Moon Bay purchase the right-of-way from Kelly Avenue south to Seymour Street.  CLT now holds the conservation easement over the narrow stretch of land, ensuring that it will remain undeveloped and open to the public.  That portion of the right-of-way and the land between there and the ocean were the focus of the workshop and walk.

The plants on the coastal bluffs reveal some of this history.  Weedy non-native plants cover much of the land on the right-of-way itself, because it has been disturbed over the years—first by the railroad tracks themselves, and later by tilling done to keep down weeds. 

West of the right-of-way is coastal wetland and coastal prairie habitat, where the land has been less disturbed and native plants are much more in evidence.  CLT, as the steward of the right-of-way, is working to return it to a more natural habitat and also to acquire the privately owned parcels of land west of the right-of-way to ensure that the land stretching to the ocean is never developed.

At the workshop, Corelli explained that there are at least 116 species of plants along the railroad right-of-way and adjacent bluffs.  Of these, the majority, almost 70, are non-natives—plants that came here from other parts of the world.  Seventy percent is much higher than usual percentage of about one-third non-natives.  (A non-native plant is identified as any plant that did not occur here naturally before European contact—about 250 years ago).

Whether introduced accidentally or deliberately planted, non-native plants can wreak havoc on our natural wild lands.  When naturalized—successfully reproducing in nature—they can outcompete and eliminate native plants. As a result, habitat essential to the survival of our native insects, birds, and other animals is destroyed. 

Non-natives' success can be due to many factors:  some spread rapidly because we don’t have the insects and animals that kept them restricted to their native habitat.  Many of the non-natives are fast-growing annuals that produce large quantities of seeds and use all available water and nutrients in the soil before our more slow-growing natives have a chance to become established. 

Several examples of annual plants competing with prolific seed production were readily apparent during the walk along the right-of-way, including and wild radish. 

One of the dominant non-natives is bristly ox tongue, which Corelli cited as one of the three most dangerous invasive plants along the bluffs.  Each of its numerous yellow flowers can produce many dozens of dandelion-like seeds which readily spread and can create a smothering carpet of plants. 

The two other invasive non-natives of particular concern, according to Corelli, are ice plant, a South African native planted deliberately along much of our coast, and Cape ivy, also from South Africa.  The latter, probably first brought to this country as a houseplant, is just beginning to get established along the right-of-way, forming a low-growing mat that can wipe out other vegetation.

Corelli also pointed out an unusual non-native invader—Italian arum or Italian lords and ladies—an ornamental, native to Europe, that is a relative of the calla lily.  It has spread from only one or a handful of plants two years ago to cover substantial areas of the right-of-way.

Corelli noted in her talk that as one moves west from the right-of-way to the less disturbed areas, many native plants show themselves and can be quite spectacular this time of the year.  These are some of our showy native plants that were seen during the walk:

+  Choris’s pop corn flower—a rare plant in the forget-me-not family that can be found in damp spots along the bluff.

+  Blue-eyed grass—not a grass, but a member of the iris family, that also favors the damp areas in the fields.  Large patches of the blue-purple flowers can be seen now.

+  Sun Cups—as their name suggests, they look like cups of sun spread on the field.  They are distinguished by their long floral tubes, which can be mistaken for flower stems.  The tubes extend from the flower to the plant’s ovaries, which are actually underground.

+  Goldfields—tiny yellow flowers that are turning areas along the into the fields of gold their name suggests.

+  Sour Clover—its inflated flower heads are quite stunning, not what you would normally expect in a clover.  Check out the photo.

+  Checker Mallow or Checkerbloom—a beautiful pink-flowered perennial that graces our bluffs briefly in the spring and then disappears until next year.

+  Lindley’s Varied Lupine—a low-growing lupine just coming into bloom.  It’s flowers can be blue and white or vary into shades of lavender, cream, and magenta, with finger-like silver leaves.

+  Sea Pink—just coming into bloom, often perched right along the cliff edge, the flowers like pink pompoms on long stems above grass-like leaves.

Words can’t do justice to these and other remarkable spring wildflowers, so take a look at the photographs to see some of what awaits you if you take a walk on the bluffs in the next few weeks.