Updated: Oct 12, 2021
Asters are a treat in autumn, mostly blooming just before chrysanthemums. Many are showy and exhibit a color range from white to shades of pink and purple. While a number of species hail from all over North America, Aster chilensis is a California native. Since this native is not in our Sunset reference, I am sharing it with you here. Let's start with the name.
While some growers sell this cultivar under the Latin name Aster chilensis 'Purple Haze,' numerous online references, including the California Native Plant Society, Calflora, and the Jepson Herbarium list its parent under Symphyotrichum chilense. This tongue-twister appears on several sources, but it is inconclusive (to me) which name is the most current. When researching Latin names, references will include synonyms and older names, usually parenthetical to the current name. This means that if one looks for information using only the latest name (in my case, I am using A. chilensis), information could be limited, since some sources may have not updated their naming. The Burke Herbarium lists Aster chilensis as a "synonym & misapplication." For our purposes, Aster chilensis 'Purple Haze' will be just fine until someone can help clarify.
'Purple Haze' as a name is well-suited for this cultivar. When in bloom, beginning in August and lasting as late as October depending upon local conditions, the small flowers appear in clusters atop grey-green to light green leaves, looking very much like a foggy drift...or in this case, a hazy drift of purple. The first photo below is from my garden, and honestly, it really does not show well in photographs. This aster, unlike most others, is very drought tolerant, but that does not mean it looks great without water. Our soil drains fast, which means our drip irrigation delivers a restricted amount of water leaving dry pockets, hence the brown leaves that can be seen in the photo. CalFlora's Taxon Report states its natural habit as freshwater marsh, probably the furthest our soil is from this desirable condition. Still, it blooms prolifically albeit sparingly throughout its season, and it is not shy about spreading. In the spring, it forms a low mat when it looks its best, out competing most weeds. I combined it with native Solidago velutina ssp. californica, and since they have the same growth cycle and blooming season, the yellow and purple is a lovely mass...apparently popular among passersby. Given its watering preferences, I would recommend locating it where moisture is more even and regularly available, where short, periodic droughts might not be so challenging. One of the few plants I have seen listed to thrive in all Sunset Zones, according to the California Native Plant Society.
Botanical Name: Aster chilensis 'Purple Haze'
Aster: Greek for star.
Chilensis: From Chile (suggesting broader origin?)
Common Name: Pacific aster; California aster
Family Name: Asteraceae
Origin: Native; British Columbia south to California
Positioning: Foreground, freshwater marsh, salt marsh, slopes, grasslands
Garden Themes: Riparian, coastal, cottage, cutting, pollinator, native, Mediterranean, dry
Uses: Border, mass, accent, ground cover, embankment cover, filler
Type: Herbaceous perennial
Form: Spreading mat, erect when in bloom
Size: 24" tall and spreading
Outstanding Feature(s): Flower, drought tolerance
Stem: Green, red, rhizome
Margin: Serrate with microscopic directional hairs
Color: Medium green
Flower: Summer to Autumn. Heads of daisy-like disk flowers with showy lavender rays and yellow-gold eye.
Fruit: Autumn to Winter. Very small achene.
cultural requirements, tolerances & problems
Sunset Zones: 1-24
USDA Zones: 6-10
WUCOLS SF Bay Area Hydro Zone: Very low
Texture: Sand, loam, clay, rocky
Moisture Retention: Well-drained but performs better with moisture without extended dry periods.
pH: Highly acidic to highly alkaline
Tolerances: Drought, deer, poor soils, standing water
Problems: Reseeding, spreading, may compete with other plants
Branch Strength: N/A
Insects: Not apparent at time of posting.
Disease: Not apparent at time of posting. Sample appears to have a type of black spot mottling the leaves.
citations & attributions
Bayton, R. (2019). The Royal Horticultural Society's the Gardener's Botanical: An Encyclopedia of Latin Plant Names. London: Mitchell Beazley.
Burke Herbarium Image Collection. "Symphyotrichum chilense." Burke Museum, University of Washington, Seattle. Accessed on September 13, 2021, from http://biology.burke.washington.edu/herbarium/imagecollection/taxon.php?Taxon=Symphyotrichum%20chilense.
Calflora, Taxon Report. "Symphyotrichum chilense (Nees) G. L. Nesom." Calflora, Berkeley. Accessed on September 13, 2021, from https://www.calflora.org/app/taxon?crn=10402.
Calscape. "California Aster." California Native Plant Society, Sacramento. Accessed on September 13, 2021, from https://calscape.org/Symphyotrichum-chilense-(California-Aster).
Jepson Herbarium, Taxon Report. "Symphyotrichum chilense." University of California, Berkeley. Accessed on September 13, 2021, from https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=80313.
Norris Brenzel, K. (Ed.). (2012). The New Sunset Western Garden Book. New York: Time Home Entertainment, Inc.
Water Use Classification of Landscape Species. "WUCOLS IV Plant List." University of California, Division of Agriculture and Natural Resources, Davis. Accessed on September 7, 2021.
Flowers in rock garden: "180131 26 La Jolla, Westfield UTC Mall, Native Plant Gardens, Aster chilensis 'Purple Haze' California Aster, Dudleya virens subsp hassei Catalina Island Live-Forever" by cultivar413 is licensed under Creative Commons Attribution 2.0 Generic (CC BY 2.0).
All other photos by TELCS.