There is much to say about the California poppy. One botanist from UC Berkeley found 70 different subspecies in different parts of California, each varying slightly from the others. The Jepson Manual, the most current California flora, lumps them all together, because they do cross and mingle characteristics. But losing the subspecies particular to different regions is a loss of biodiversity, and ALSO of possibilities for the native plant gardener.
I used to wonder (frequently out loud) why so many orange poppies were found in my coastal region, where I knew the type was yellow with an orange blotch at the base, or no orange blotch. Giving a talk at a garden club on that topic, I saw a woman waving her hand at the back of the room. "I grew up at the ranch that is now Audubon Canyon Ranch," she said. "Every year my father planted a huge sack (I forget now if it was 50 or 100 pounds, but a significant amount) of the orange California poppy." "Oh," I said. Mystery solved.
Throughout California, literally tons of the orange-flowered annual type most frequently thought of as THE California poppy, and possibly originating in Antelope Valley in souther California, were sown by Boy Scouts, by garden clubs, by landowners, by gardeners, inadvertently swamping out the individuality of each area's own form of the California poppy. Some were even dropped from airplanes, as "beautification" measures.
It has been so interesting to grow our own form on the coast. As a perennial, it behaves quite differently from the annual inland orange form (I am referring to them as "forms" since the subspecies have been eliminated taxonomically, at least for the moment). The tap root can get immense, as long as two feet, and thick as a baseball bat (which we have experimentally used it as).
In dry years, it flourishes, and I used to worry that it was too aggressive, eliminating other wildflowers. Then I observed that in wet years, it was substantially knocked back, because it doesn't like wet feet. Now I just relax, counting on an ebb and flow of the coastal form of the California poppy, so that it is only one element among many in the garden.
The bouquets must be seen to be believed. Some flowers open 4" wide by the end of their time in the vase. Many songs have been written in praise of the California poppy, but none seem to mention the distinction between Eschscholzia californica and Eschscholzia californica var. californica, formerly, var. maritima. It probably doesn't scan well.