One of the annual favorites at CNPS-SLO is a field trip to the coastal bluffs along Highway 1, roughly two miles north of the bridge that spans Arroyo de la Cruz. This outing has been held either in May or June each year, depending on the seasonal temperatures and precipitation. This year, we experienced above normal temperatures and below normal rainfall throughout the winter and early spring. Flowering times were roughly six weeks earlier than the average, so we planned our visit this year for the third Sunday of May.
Despite climate irregularities, we found an incredible display of late season wildflowers and rarely seen perennials. Thirty-five plant enthusiasts turned out to hear a local legend, D.R. “Doc” Miller, speak about the unique flora of this amazing one square mile of land – framed by Highway 1, by the Pacific ocean, and a few small creeks that cut across the bluffs from east to west.
When asked why this spot has such an abundance of rare plants year after year when nearby areas with similar soil type do not, Dr. David Chipping, retired Professor of Geology at Cal Poly, commented it is because this area was never ploughed. This led us to understand that the disturbances of modern agriculture have altered many California landscapes over the past centuries. So, one wonders what other rarities might have been buried for good in these rich and diverse landscapes.
As we jumped out of our cars along the highway, we were greeted by scores of lemon yellow cups, the yellow mariposa lily (Calochortus luteus), which occurs here near the southern end of its range. Each flower had hundreds of brick red and orange flecks of color along with hundreds of small, velvety hairs, as well as six stamens arranged symmetrically around a three-pointed stigma. This was a very handsome lily!
From here, we encountered one of the real novelties of these coastal bluffs, the dwarf goldenstar (Bloomeria humilis). These flowers resemble their taller cousins (B. crocea) found more inland, but these are only four inches tall. This plant is extremely rare, having a CNPS rating of 1B.2 (rare, threatened, or endangered in California), and are only found near the junction of Monterey and San Luis Obispo Counties.
In the same area, we found a mixture of the lovely dwarf blue Brodiaea (B. terrestris), a prostrate pink Farewell to Spring (Clarkia prostrata), two morning glory species, Coast Morning Glory (Calystigia macrostegia var. cyclostegia) and San Luis Obispo Morning Glory (C. subacaulis var. episcopalis). This is a rare CNPS rank 4.2 (fairly endangered in California) found only in San Luis Obispo and Santa Barbara Counties. We also found an unusual pink and white Acmispon, Bentham’s Lotus (A. cytisoides) and the always erect and multi-branching yellow Coast Gum Plant (Grindelia stricta) with large, immature buds filled with its signature resinous liquid.
Next, we focused a very uncharacteristic Apiaceae species, also nearing the southern end of its range, the coast Eryngo (Eryngium armatum). This plant grows very close to the ground, has gray-green foliage, and is covered with heavily serrated or toothed leaves and spikey inflorescences, each surrounded by several long, sharp-pointed bracts. If one were to walk these bluffs barefoot, it would be impossible to go more than a few steps with these pokey plants under foot.
We were then treated with the opportunity to meet two woody perennials that only grow in the northwestern corner of San Luis Obispo County. Both are CNPS 1B.2 ranked. The first was Ceanothus maritimus, the Maritime Ceanothus, which grows so close to the ground among the coastal grasses that it is easily to ignore. The second was the very handsome Arroyo de la Cruz Manzanita (Arctostaphylos cruzensis) of which we found only one individual growing on a slope dropping down into one of the creeks.
Some other beauties along the way were the two blue-eyed grasses, one with blue flowers (Sisyrinchium bellum) and the other with yellow flowers (S. californicum). While the blue flowering plants were wide spread on the bluffs, its yellow cousin was found only in moist areas along the creeks.
On the very edges of the bluffs above the breaking surf, we found several beauties. There were a number of Dudleya in bloom. Doc Miller said he wasn’t sure about the exact identification of this species, as it is common for three in the area to potentially hybridize. These are D. palmera, D. lanceolata, and D. caespitosa. We also found plentiful quantities of the succulent Pacific Seaside Plantain (Plantago maritima), something that resembles a small dudleya, with nearly linear leaves, but with a completely different, spadix-like flower. This native Plantago is also nearing the southern end of its range of occurrence.
Two other plants that dazzled our eyes were the big-flowered Seaside Daisy (Erigeron glaucus), which we found hanging on the cliffs right above the water and the large, indigo-flowering Douglas’ Mesamint (Pogogyne douglasii), with its strongly scented leaves, similar in aroma to Coyote Mint (Monardella).
We also encountered two parasitic plants in full flower on these bluffs. One was Dodder or Goldenthread (Cuscuta pacifica) with small, white flowers, the other was the rarely seen California Broomrape (Orobanche californica) with a surprising profusion of large, tubular lavender flowers.
One more prize, which appeared towards the end of our walk, was the Compact Cobweb Thistle (Cirsium occidentale var compacta) with its flush of burgundy colored, tubular corollas and white tips, that gave the impression of newly fallen snow flakes.
Many of us at CNPS are passionate about preserving pristine patches of wonder in our state. This location, north of Arroyo de la Cruz, is a fairyland of highly valuable real estate, due to its floral diversity and one-of-a-kind biology. We are grateful to Doc Miller and the CNPS organization for their efforts in public education, highlighting the splendor of such areas – places we could have easily missed or ignored. And how fortunate it is, that some unknowing farmer did not plow down this spot many years ago and that now, these coastal bluffs are protected forever, as State Park land.
Doc Miller passionately displays an attractive Seaside Daisy (Erigeron glaucus)
Article written by B.Waycott, photos by B.Waycott, except B.terrestris c/o tmousecmouse, S.californicum c/o D.Wimpfheimer, C.maritimus c/o A.Sims, and A.cruzensis c/o S.Matson