First, what do I mean by "annuals"? These are plants that germinate (sprout) from a seed, produce a flower and new seeds, and die within the same year. They leave behind no living stem or roots, only seeds. In southern California, annuals (sometimes referred to as annual wildflowers) have a good strategy for dealing with the summer drought. They are called "drought avoiders" because the plant itself doesn't have to try to make it through the dry season. Only the seeds must deal with the drought, and because they are self-contained life systems with very slow metabolism, they don't have a problem with months or even years of drought. When the rains come, they are ready to spring back to life.
A classic example of this phenomenon is the California Poppy (Eschscholzia californica), the official State Flower. Below is a shot of some of the poppies in my yard in 2010.
California Poppies are extremely easy to grow. You can buy the seed at just about any nursery or home improvement store. They germinate readily, they are popular with bees and other pollinators, and they produce copious amounts of seed for the next year. But be careful or they will take over your whole yard. My advice is to thin the seedlings to about 6" apart for best results, and mercilessly pull them out of areas where you may not want them.
There are a few recognized subspecies and/or varieties of California Poppy, and some of these are still under debate by botanists. For purposes of this blog, it is sufficient to say that there are some color variations between flowers from different parts of the state - some flowers have more yellow in them. For the average home gardener this doesn't matter. But if you live near the Antelope Valley Poppy Preserve, you should be careful to use only seed from local flowers. This is to avoid genetic contamination of the wild poppies.
The next annual on my list is a genus with approximately 139 taxa (species, subspecies, etc.) from throughout California and the West. It is the Lupines. The species in my garden is Lupinus succulentus, otherwise known as Arroyo Lupine. It is quite widespread in the wild in California, and it makes a great annual for the garden, producing a tall, showy flower stalk.
Lupines are in the pea family (Fabaceae), so after flowering they produce a characteristic pea pod containing several large seeds. You can either let these seeds fall to the ground or you can collect them for sowing elsewhere.
Another sure-fire annual to try is Chinese Houses (Collinsia heterophylla). It is in the Plantain family (Plantaginaceae).
I have only grown this one for a couple of years, but my experience with them so far is that they are great. They germinate readily and early, the flowers are small but gorgeous, and they reseed readily. They work best when massed - they form a temporary ground cover to about a foot high. So pick an open area with lots of sun and sow the seeds rather densely there.
Here's another annual that I love - Tidy Tips (Layia platyglossa). It is in the aster/sunflower/daisy family (Asteraceae) which is an enormous family of great plants. In a previous post I have already talked about this family as "composites" so I won't go over that again. I'll just say that Tidy Tips is another winner for the home garden.
The last annual for today is from the primrose family (Onagraceae). It is Clarkia bottae. There are about 70 Clarkias in California and this is just one of the good choices for the garden. Like the other annuals I have described above, this one is easy to grow and yields great results.
I like these Clarkias mixed with other annuals and perennials, as in the photo below. There are California Poppies (both solid orange and yellow-orange although this photo exaggerates the difference), Clarkia,(pink) and a perennial called Beach Evening Primrose (smaller yellow).
I mentioned that California Poppy seeds are easy to find, but some of the others are not. If you want to try to native annuals, the place to go is the Theodore Payne Foundation (theodorepayne.org). This organization's mission is to help spread the word about native California plants, and they have a huge selection of seeds to choose from including several more species of Clarkia, Lupines, etc. I highly recommend that you give them a try.