Symphyotrichum chilense (formerly Aster chilensis), is also known as common California or Pacific Aster, and is native to the western United States, found from central California, northward to British Columbia. This species is commonly found in open dry site plant communities, including coastal sage scrub, coastal salt marshes, freshwater marshes, and mixed-evergreen forests.
Pacific Asters grow from 1 to 3 feet in height, and their flowers emerge between mid-June and October.
Leaves are slightly hairy, semi-elliptical to lanceolate in shape, and slightly toothed along the margins.
The inflorescence is comprised of cymes. Cymes are flat-topped clusters of flowers where the central flower bud opens before the surrounding ones, as shown below. Each bloom is a compound flower with violet, lavender, or white rays, surrounding a cluster of yellow disk flowers. Each ray measures approximately 6-12 mm in length.
Some native plant nurseries do stock this species, which provides an excellent nectar source for a variety of beneficial insects and butterfly species, including the Field Crescent and Northern Checkerspot. The lavender form is generally more common than the white form we have growing here.
Pacific Aster is not well suited for formal areas, but this plant is a good filler for meadow gardens, in dry areas, and can be used to help stabilize slopes. It is a drought-resistant, and vigorous, perennial, spreading both by seed, and via underground rhizomes. In the wild areas of the property here, including our slopes above the orchard, this plant should remain reasonably well behaved, even in the absence of deer. However, in cultivated gardens, in rich soil, with occasional supplemental irrigation, this native Aster species can become very unruly and invasive.
Although I haven’t been able locate any ethnobotanical data relating to this particular species, a number of native Asters have had a variety of uses by native peoples. The Blackfoot Indians used infusions of Aster as a gastrointestinal aid, and to treat their horses or dogs with sinus disorders. An infusion of Aster was also used by the Blackfoots as an eye wash to treat dogs with eye infections. Flowers were used to make necklaces, and the Chippewa apparently boiled the leaves with fish and ate them. 
Note that some nurseries report this to be a deer resistant plant, however, here our deer clearly didn’t receive that memo, and the only plants we’ve found blooming are within our fenced area. Perhaps now that some of these plants at least are secure from browsing deer, hopefully we’ll see a few more blooming next year.
 Daniel E. Moerman’s Native American Ethnobotanical Database