Members of the poppy clan are hard to tell apart, and it is easy to confuse them. The California poppy (Eschscholzia californica subspecies californica) has been California's official state flower since 1903; the Mexican poppy (Eschscholzia californica subspecies mexicana) is both a lookalike and a subspecies of the California poppy. Like the California poppy, it is native to California.
California Poppy Subspecies
Low-growing, with four, silky, orange petals, the California poppy is among the best-known flowers in California. The California subspecies is native to the West from Washington down into Mexico while the Mexican subspecies thrives in hot, dry regions, including the Sonorian Desert. Scientists believe that the two subspecies were isolated about 8,000 years ago after the last glacial period. .
According to experts at the Lady Bird Johnson Wildflower Center, the two poppy subspecies are exceedingly similar. One way to tell them apart is by their habitat. The Mexican poppy prefers dry desert areas while the California poppy also grows in valleys, on hillsides and in coastal areas. Another consistent difference is that the first leaves on Mexican poppies are linear and undivided while those on California poppies are split into a Y shape.
California poppies grow in a wide range of climates, thriving in U.S. Department of Agriculture plant hardiness zones 5 through 10. With their bright-orange flowers, the plants grow well on poor soil as long as it is well-drained and the site is sunny. They self-seed regularly, achieving huge populations on open tracts of land. The species propagates so freely that it is deemed potentially invasive in parts of the United States and in Mediterranean climates around the world.
The Mexican poppy grows as an annual. Like the California subspecies, it self-seeds regularly and forms large colonies on accessible land. Due perhaps to the fact that it prefers dry, desert lands, however, the Mexican subspecies never has been labeled as invasive.
- Lady Bird Johnson WIldflower Center: Eschscholzia Californica Ssp. Mexicana
- Floridata: Eschscholzia Californica
- California Invasive Plant Council: Rapid Evolution of Invasive California Poppies
- U.S. Department of Agriculture, Natural Resources Conservation Service: California Poppy
- Encyclopedia of Life: Facts about California Poppy (Eschscholzia Californica)
- Invasive Plants Atlas of the United States: California Poppy
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