California native plants are plants that existed in California prior to the arrival of European explorers and colonists in the late 18th century. California includes parts of at least three . The largest is the California Floristic Province, a geographical area that covers most of California, portions of neighboring Oregon, Nevada, and Baja California, and is regarded as a "world hotspot" of biodiversity.
In 1993 The Jepson Manual estimated that California was home to 4,693 native species and 1,169 native subspecies or varieties, including 1,416 endemic species. A 2001 study by the California Native Plant Society estimated 6,300 native plants. These estimates continue to change over time.
Of California's total plant population, 2,153 species, subspecies, and varieties are endemic and native to California alone, according to the 1993 Jepson Manual study. This botanical diversity stems not only from the size of the state, but also its diverse topographies, climates, and soils (e.g. serpentine outcrops). Numerous plant groupings exist in California, and botanists work to structure them into identifiable ecoregions, plant communities, vegetation types, and habitats, and taxonomies.
California native plants include some that have widespread horticultural use. Sometimes the appreciation began outside of California—lupines, California fuchsias, and California poppies were first cultivated in British and European gardens for over a century.