The weather in California is mostly worm and you are always told that the worst time to plant is in the summer. This is due to the fact that the weather is so hot that there is a high likely hood that the plants you plant in the summer may not fare well. So what you do then? Enjoy the colors of summer. You can plant the rest of the year to have color within each season.
Remember that you are only limited by your imagination and that these 3 plants I am sharing are only a sniped of the vast variety of plants that are available to choose from. Just make sure that with any plant that you put it in an area where it will have room to mature and grow and get the right amount of light that it needs. For example a plant that gets 5' tall should be planted to have a 5' diameter space of room go grow.
If you are interested in other seasonal plantings then click on the appropriate season.
Fall seasonal planting.
Winter seasonal planting.
Spring seasonal planting.