California Aster
Corethrogyne filaginifolia
Care
full sun, part shade
very low
Fast, Medium, Slow; Tolerant of sand and clay.
0–3ft tall , 1–6ft wide
Jan-Dec
Evergreen
Resistant
Friendly
Prized
Coastal scrub and bluffs from San Luis Obispo County to San Diego County, below 1500 ft elevation along the Pacific coast.
Care Guide
Planting
Plant California Aster in full sun on a sloped or rocky area rather than flat ground - it thrives on dry slopes surrounded by rocks and will often stay beautiful year-round in these conditions. It tolerates sandy and clay soils equally well and will perform in fast, medium, or slow-draining soil, though good drainage is important. Plant in fall or early spring to establish before summer heat.
After Planting
Water weekly during your first summer to help it establish, then stop - this plant is very drought tolerant once established and cannot tolerate summer water, which will often kill it after its first year. Year 1 is critical: the biggest mistake people make is continuing to water during summer heat, which will kill the plant. After establishment, never irrigate during summer months. The plant is evergreen and will bloom throughout the year if happy, occasionally reseeding into nearby rocky spots.
Endangered & Threatened Species Supported
California Dogface butterfly, state insect
California endemic, limited range
California Species of Special Concern; monarch populations declining
Wildlife Supported
Insects
California endemic; larvae develop on aster species in spring and early summer
Fall migration staging fuel September-October; critical nectar source for long-distance migrants
Adults nectar throughout blooming period; important fuel source during multiple flight periods
Multiple broods; important nectar source during flight periods
Adults nectar throughout flight season; important late spring/summer resource
Spring and early summer blooms provide adult fuel
Adults visit flowers during spring and early summer activity
Multiple generations; consistent nectar visitation throughout blooming season
+1 more species