The most suitable time of year to do native planting is during the typical rainy period here in Southern California. Fall season normally is the start of the winter rain and with our warm days and cool nights, the establishment of native plants and the survival rate is greatly increased as the plants rooting system is active and top growth is limited due to the short sunlight periods of time through the fall days. Spring time is also a great time to do plantings of natives and the winter rains help keep the plants well hydrated. As we move into the warmer months of the year, it is advisable to take note of what types of natives you are attempting to install and understand that plants blooming period. Work at adjusting your installation time to duplicate the native plants natural cycle of growing and blooming. It is better to plant before it blooms than just before in my opinion. With the warmer summer months, it becomes difficult to balance the natives actual water needs ( Some native receive almost no supplemental water at all during the warmer summer months ) and the actual moisture needs of the plant due to evapotransporation of the applied water to the plant. Some folks and contractors for that matter, tend to over water the native due to the need to keep the plant alive but the natural characteristics and requirements of the native is to not receive as much water as it is receiving thus leading a lot of times to plant failure and death.
keeping these thoughts in mind will help you better plan your native plant installation time and give you a better success rate when it comes to the survival of your plant materials.