>>2856229Plants generally adapt to locales that they have been present in for thousands of years. The exotic fruit and nut trees from the middle east can still grow in California's climate without irrigation, but they will take longer to grow and have much lower yields. Since agriculture is largely focused on profit in the USA, not subsistence, growers obviously go for the quick and easy approach even if it is ecologically devastating in the long run.
Ironically however, native plants in Arizona and parts of California as well as parts of Sonora and Baja in Mexico are the most drought adapted plants on Earth, capable of being invasive in the Australian deserts and parts of the Sahara ( SW AZ and S CA are SUNNIER than the Sahara). But these are less desirable and less palatable crops.
-Amaranth (especially northern varieties, ie drought hardier)
-Arizona grape (possibly hardiest on Earth)
-Velvet and Honey Mesquite (hardy, nitrogen fixing, edible legumous trees)
-Tepary bean (hardiest on Earth)
-Jojoba nut
-Pinto bean and relatives
-Sweet potato (Ipomoea, ie Morning Glories native to northern Mexico, CA, and AZ which has 12 species)
-Jerusalem artichoke (Sunflower family with tubers also see relatives like Smallanthus sonchifolius)
-Native squashes (eg Cucurbita foetidissima, found in climates that only get 10 inches of yearly precipitation)
-Prickly pear (especially Opuntia Engelmannii prolific delicious and universally hardy to everything, Opuntia fiscus indica less drought hardy but prolific, you can plant a single pad and it will become a 7ft tall cactus in 3 years)
-Sonoran desert Wolfberry (Lycium fremontii and Lycium andersonii, edible raw when ripe)
-Desert Ironwood (Olneya tesota, requires boiling two times for ideal edibility, but is also one of the hardiest plants on Earth)
-Linum lewisii (desert flax/linen)
-Thousands of tea flowers
AZ and CA have possibly 6,000+ *distinct* native plant species (of 9,500 known native species to date).
