California is a big place, with more environmental diversity than any other state and most other countries. It includes rainy and cool forests of Del Norte County, and dry and hot deserts of Imperial County. The snowy mountains of Placer County and the mild coastal plains of Los Angeles County are here too. There are hundreds of miles of sandy beaches and big fertile valleys.
Consequently, plants that are native to California are just as diverse. Many that are very well adapted to the environments that they naturally live in are not so well adapted to other environments that may be only a few miles away. They really do not want to go to some of the more divergent climates in other regions.
Coastal redwood that is so happy within its natural range on the foggy western slopes of the coast ranges to the north are not so happy on the drier eastern slopes of the same ranges. It probably would not survive for long in the Mojave Desert. California fan palm from the hot and arid region of Palm Springs languishes on the damp and cool western edge of San Francisco.
Most of the popular California native plants are popular because they do not need much water, if they need any at all. However, some are as unhappy with local climate conditions as exotic plants from other continents are. For example, few plants tolerate drought as well as Joshua tree does. Yet, Joshua tree is likely to grow fast and then rot because winters are too damp for them locally.
Of all the excellent plants that are native to California, the most excellent for local gardens are either the few plants that are native to the local region, or the many others that are native to similar regions. They do not need cold Sierra Nevada Winters, hot Death Valley summers, Mojave Desert aridity or San Francisco fog. They are right at home here.
Even natives need some help adapting to a new garden. Confining their roots to cans while they grow in nurseries is very unnatural for them. Once planted, they will need to be watered while their roots disperse enough to survive on rainfall, or with minimal watering.