This is a compilation of our own observations and a little bit of research online. It is a place to start if you want to plant a bee garden or are interested in planting native bee plants to increase native pollinators in your garden or orchard. If working with bees in California use a beesuit.
There are one thousand species of California native bees, 26 of these are bumblebees and most of the rest are solitary bees. That is, they do not live in a hive with drones and all the rest. Some bee species are very specific in their needs. Andrena limnanthis Hesperandrena, a native solitary bee, visits only specific species of the vernal pool flower, Meadow Foam, Limnanthes sp. The native bees will prefer natives from their area. Some bees are very restricted in their range and may not know what to do with stuff that is too far removed from their home, even if it is native to California. Many other native bees will work the available flowers that are in the families of flora they are used to.
Bee society and nesting
Solitary bees usually nest in the ground, in holes they excavate themselves or in old rodent holes. A single female will prepare her earthen nest, build a few cells, lay her eggs, and collect pollen for them. Sound familiar? Although they nest alone, many females may lay in the same area. So if the area is good for native bees you may end up with bumblebee, digger bees and mier bees all living next to each other. Because many bees nest in the ground, don't disturb the soil by tilling or scraping. These actions will also encourage more weeds. You want clean bare ground with no European grasses, Mustard, Star thistle, etc. Native wild flowers are Ok. .See also Digger Bee