Southern California’s warmer months would be a little duller without bougainvillea. Every spring, the region’s gardens erupt in a riot of color as these thorny climbers bloom and their papery, leaf-like bracts (distinct from the plant’s tiny white flowers) burn deep red, bright magenta, even “California gold,” draped over fences, dripping from pergolas.

Native to tropical South America, the plant owes its name to Louis Antoine de Bougainville, commander of an expedition that circumnavigated the globe in 1766-69 and, while anchored off Rio de Janeiro, recorded the first scientific observations of the colorful vine.

Despite the plant’s French spelling, California has long imposed a Spanish accent on the bougainvillea. In the early 20th century, writers and gardeners romantically imagined the plant as a living ghost of California’s mission era. Riverside hotelier Frank Miller, for example, made liberal use of it at his Mission Inn (built 1902-32), where red bougainvillea still flows today from balconies like botanical waterfalls. Poet Adeline Marshall Durlin’s ode to the plant, published by the Los Angeles Times in 1922, succinctly captures its Spanish-fantasy associations:

Passing into decay is the Bougainvillea vine.

How we miss the splendor of its graceful climb,

It takes us back to Padres, passing to and fro,

Under Mission patios of the long ago.

In truth, it’s uncertain whether those “Padres” ever knew the pleasure of a brilliant mass of bougainvillea. With their ornamental plants and formal designs, California mission gardens today suggest they have always been landscapes of leisure and contemplation, admired by strolling priests then just as they are by tourists now. In fact, those gardens were an invention of late 19th-century romantics. In Spanish-colonial times, mission patios were typically productive, not ornamental landscapes, the site of forced labor by indigenous people. Bougainvillea may have graced colonial California – after all, it was already a popular ornamental in Mexico by the 1800s, and networks of botanical dispersion permeated New Spain – but it was likely a much later addition to mission landscapes.

As a commercial nursery plant, bougainvillea probably first came to California as seeds or cuttings from its native Brazil by way of Australia in the 1860s, long after the last Spanish flag was lowered over California. By the 1880s it had become a favorite of horticulturalists intent on “emparadising” the region – a process, as Jared Farmer describes in his history of “Trees in Paradise,” of introducing exotic evergreens and multi-hued flowers to correct a landscape they perceived as too barren and brown.

One of the earliest written descriptions of a California planting comes from the April 1, 1881, edition of the Santa Barbara Morning Press, which reported that “two beautiful specimens of the Bougainvillea, whose rose-colored bracts when in bloom attract so much attention, were growing side by side” in the De La Vina Street garden of physician L. Norton Dimmick. Just three years later, in 1884, San Jose nurseryman R. D. Fox advertised the same two varieties, B. specula and B. glabra, in his catalogue.

Soon after the the turn of the century, elaborate bougainvillea plantings were aiding California’s self-promotion as a semi-tropical paradise. In Glendora, beginning in 1901, bougainvillea climbed the lanky stalks of Mexican fan palms along a 1,200-foot stretch of roadway. In Los Angeles, the parks department claimed in 1906 to be tending the world’s largest bougainvillea display: a 200-foot-long trellis clothed in purple.

Bougainvillea had its champions across California – especially in the warmer south, where the frost-intolerant plant was more likely to thrive. Los Angeles Times agricultural editor J. W. Jeffrey, for example, advised his readers in 1902: “If there is room upon the outer wall of your residence for but one plant, let that be a Bougainvillea…There is no danger of getting too many of these beautiful purple flowers.”

But bougainvillea found its most devoted apostle in Kate Sessions. The San Diego horticulturalist is credited with popularizing that other springtime spectacle, the jacaranda, as well as the bird of paradise, now Los Angeles’ official city flower, but she reserved special praise for the bougainvillea.

Through her writings and her plantings, Sessions encouraged Californians to design their gardens around the vine. Because of its bold colors, she wrote the plant should be given its own trellis or arbor or even be allowed to overtake a side of a house. “Don’t discard the bougainvillea, but put it in the right place, and you will have a plant of oriental splendor,” she admonished her readers in her “Notes on Planting” column for the San Diego Union in 1891. The following year, Sessions opened a garden and nursery on 32 acres of San Diego’s City Park – some of the first improvements in what would later become Balboa Park – and experimented there with several new varieties of bougainvillea, all on public display.

Sessions traveled often on business to Los Angeles and spread the gospel of brilliant bracts there, too, but San Diego, with its hotter climate, remained the bougainvillea capital of California. Never was that more apparent than during the city’s Panama-California Exposition, which Balboa Park hosted from Jan. 1, 1915, to Jan. 1, 1917.

During those two years, bougainvillea – when in bloom, at least – caught the eyes of tourists throughout San Diego. Home gardens exploded with color, thanks to a City Beautiful campaign the previous year that gave away hundreds of choice clippings to residents. The exposition grounds themselves, designed in part by landscape architect Paul Thiene, featured two dramatic displays of bougainvillea: red along El Prado, the fair’s main walk, and purple on the central Plaza de Panama. The bold colors not only contrasted nicely with the white walls of the fair’s Spanish Colonial Revival architecture – they must have also burned a lasting impression in the minds of the exposition’s 3.7 million visitors.

Soon, bougainvillea was brightening gardens across southern California, from Mission San Juan Capistrano to the Mission Inn, its dripping vines signaling each year in bright colors that springtime had arrived.