This native of the western United States throughout California, extending to Oregon, southern Washington, Nevada, Arizona, New Mexico and in Mexico in Sonora and northwest Baja California likes poor, sandy soils to grow in.
The US Formulary of 1918 says of this plant:
“Attention has been brought to this California member of the Papaveraceae, as a powerful- herb for calming and supporting sleep”
Native American tribes from different parts of California used this plant for many medicinal purposes especially as a calming agent. The Pomo tribes (from areas north of what is now Sacramento) reportedly used the crushed seeds as a topical application, while the Mendocino used a root preparation as an external cleansing agent. It was used by the Costanoan tribes (from what is now Monterey) to promote healthy sleep (Soporific) and rubbed a decoction into the hair to kill lice. It has a long tradition of use in Western Botanical medicine as a Nervine and Trophorestorative (promotes nutrition uptake at the cellular level).
Several Native American tribes boiled the plants or roasted them on hot stones to be eaten as a green. The seeds were used in cooking. Some caution has been recommended when using this plant since it belongs to a family that contains many poisonous plants.
The California poppy is the California state flower. It was selected as the state flower by the California State Floral Society in December 1890. A natural food coloring, poppy petals also makes a fugitive (doesn’t last) dye that can be good for making “photos” on paper. Extract the color from the petals with alcohol. Paint on paper. You can then place a positive (instead of a negative) like a piece of lace, a paper cutout, or a leaf over the paper and set it in a sunny place for a week. The parts that are covered will remain purple, and the rest will fade. This process was used experimentally in the 1840s before photographs as we know them were invented. It produces what is called an anthotype