CHANGES IN LATITUDE Super Bloomin’: Baja’s Central Desert Puts on a Rare Show
by Ken Carloni
As a botanist and ecologist, experiencing a desert super bloom has been high on my bucket list, but has proved to be an elusive prize. Exacting weather conditions must be met in the preceding year, and timing must be precise to produce a profusion of synchronous wildflower blooms. Unfortunately, with a job, a home, and gardens to keep up with, I couldn’t just pick up and race off to the desert when one occurred (about every 10 years in different deserts). Over the years, our pre-arranged trips to the deserts of North America tended to align with droughts. Stark beauty, indeed. But “stark” and “wildflower” are words that are not often associated…
Fortunately, retirement has expanded our travel timing options, and this February we got lucky in the Valle de los Cirios (“Valley of the Candles”) Biosphere Reserve in Baja’s Central Desert.
Why are desert super blooms so rare?
To the uninitiated, deserts are often regarded as arid, barren landscapes devoid of life and color. However, every so often, these seemingly desolate regions transform into vibrant tapestries of blooming wildflowers. This captivating event is the result of a perfect convergence of environmental conditions. Below, we will explore the key factors that must align to bring this breathtaking spectacle to life.
- Adequate Rainfall:
The primary prerequisite for a desert super bloom is an exceptional amount of rainfall. Deserts are known for their low precipitation levels, making water a scarce resource. However, when unusually heavy rains occur, they saturate the parched desert soil, awakening dormant seeds and triggering germination. These seeds may lie dormant for decades, patiently awaiting the right conditions to germinate. The “atmospheric rivers” that pummeled the West for the last two years met this condition in spades.
- Timing is Crucial:
Timing plays a crucial role in the desert super bloom phenomenon. The rain must arrive at the right time — usually in the winter or early spring — when the desert plants are in their dormant or semi-dormant states. If the rain comes too late, the plants may have already exhausted their stored energy reserves or entered their reproductive cycle, missing the chance to capitalize on the newfound moisture. Alternatively, if the rain arrives too early, or is followed by an extended dry period, winter annuals may not survive to bloom in the spring. This happened after the heavy fall “monsoons” in the Sonoran Desert in 2021-2 were followed by a dry spring. Seeing all of the rain sweeping across the Southwest on the weather maps, Jenny and I made plans to visit friends and family in the Tucson area that spring. But alas – another swing and another miss. The landscape was awesome, but hardly a bloom was to be seen.
- Temperature and Sunlight:
Following rainfall, favorable temperature and sunlight conditions contribute to the success of a desert super bloom. Mild temperatures and abundant sunlight are crucial for photosynthesis, the process by which plants convert sunlight into energy. Consistent moderate temperatures provide an optimal climate for the growth and development of flowers, allowing them to blossom and flourish. Extreme heat or frost can hinder the bloom by causing stress or damaging the delicate flowers.
- Lack of Grazing:
To witness a desert super bloom, it is essential that livestock grazing be limited or absent, and native grazers managed effectively, at least during the bloom period. The more growth plants can keep each year, the more energy they can put into flowering and dispersing their seeds for future generations. Fortunately, the Valle de los Cirios is a UNESCO-designated biosphere reserve (https://simple.wikipedia.org/wiki/Biosphere_reserve) where livestock grazing and other human activities are highly restricted.
As often happens in life, you find what you are looking for when you are not looking for it. Our previous trips to Baja were always constrained by our academic schedules, so Spring Break was always late March. We’ve seen some great botany down there, but always in the oases or other nooks and crannies in subdued numbers. So we planned our trip this spring to better coincide with gray whale calving in Laguna Ojo de Liebre (always a thrilling experience), with only the faint hope of better than average flora.
On Valentine’s Day 2023 we scraped the snow off the roof tent on our trusty Tacoma and turned south. Alternately camping one night and staying in a motel room (with something like hot showers) the next, we cruised south through mostly familiar territory with some fun side explorations. The weather was unusually cool and overcast, and we got deluged in Mulegé. Our botanist friend Debra Valov kindly put a mattress on the floor for us, and remarked on how unusually heavy the rain had been.
Free of spring break constraints, we had the time to go all the way south to Cabo Pulmo National Marine Park, the only hard coral reef on Baja’s Gulf of California shoreline. I wrote the brief article (https://umpquawatersheds.org/more-on-forest-thinning-for-wildfire-resistance-or-not/) for the previous issue of 100 Valleys sitting outside a bungalow in Cabo Pulmo, and noted that we were there to see the reef while it is still relatively healthy. The day after I sent that in, we caught a break in the weather and snorkeled with at least 25 species of many-colored fishes. A big check off on the bucket list, but I can’t remember the last time I shivered that hard from the unseasonably cold water. I’ll tell the rest of these stories in future Changes in Latitude installments… Stay tuned!
On our way back north, we passed through the area that had rained so hard on us. We had glimpsed some color on the way south, but time obligations and the Trans peninsular Highway (that generally has no shoulder and few pullouts) had kept us from investigating. I was looking hard, and just when I thought we had missed it, the desert exploded in color. And what made this carpet of vibrant color on the desert floor even more other-worldly was the backdrop of “trees” that dotted the landscape. The main “overstory” species can reach over 60’, and include a gang of bizarre characters straight out of a Dr. Suess book.
The iconic Cirios (Fouquieria columnaris), for which the reserve is named, are also known as Boojum Trees in English. The name means “Candles” in Spanish, and is descriptive of the plant’s shape, which has been described as a giant pale green upside-down carrot. Most branches are less than 2 feet long and form a thin brush up the length of the gradually tapering spire. Older trees often branch into several umbrella-like fingers at the top.
Often mistaken for Saguaro cactus, the massive Cordón (Pachycereus pringlei) has many “arms” that stay close to the main trunk in a columnar form. These bat pollinated cacti provide large, sweet fruit to the desert community, and were a staple of Baja’s indigenous peoples’ diets.
The spiky Baja California Tree Yucca (Yucca valida) and the squat Elephant Tree (Pachycormus discolor) round out this fantasy forest. Tree Yuccas have lance-like, sharp-tipped leaves that surround their few large branches and bend downward as they age to form skirts below the living leaves. The elegantly gnarled Elephant Tree has a broad, contorted trunk, with thin greyish peeling bark. Its large, snaking branches support comparatively small leaves that are produced and dropped according to soil moisture.
Most desert landscapes have blooms dominated by one species of herbaceous flowering plant (think California Poppies in the Mojave Desert) mixed with several other common species. In Baja’s Central Desert, this is often the Desert Vervain (Glandularia goodingii). These striking clusters of magenta blooms are interspersed with bright red Hummingbird Flower (Justicia californica), orange Apricot Mallow (Sphaeralcea ambigua), deep purple Baja California Nightshade (Solanum hindsianum), canary yellow Thick-Leaf Groundcherry (Physalis crassifolia) along with a couple of dozen smaller, but no less striking, wildflowers tucked into the mix. The photos here are selections of the several hundred shots I took while wandering in awe of this desert wonderland.
Gritty Central Desert soils are derived from coarse granite crystals eroded by wind from the dramatic boulders strewn across the landscape. These soils have lots of pore space to absorb water, but their porous structure also causes water to drain away quickly. Plants have to be primed by previous rain to build the roots and leaves necessary to capture that water to power profuse blooming. The atmospheric rivers that hammered the west coast all the way down to Baja produced the steady water supply and cool, even temperatures that had blessed that particular high-diversity microclimate in a reserve managed for biodiversity.
The occurrence of a desert super bloom is a mesmerizing testament to the resilience and adaptability of nature in a harsh and demanding landscape. This ephemeral spectacle not only enchants those lucky enough to be in the right place at the right time, it also provides essential nourishment for pollinators, a subsequent burst of seed for birds and other animals, and a large deposit into the soil seed bank for future generations. Although we saw beautiful wildflowers in other parts of our tour, a series of extraordinary circumstances happened to intersect with our journey –abundant rainfall, optimal timing, favorable temperatures, and limited grazing — that caused a stark desert landscape to burst into a magnificent display of colorful wildflowers.