California Milkweed
Asclepias californica
Care
full sun
very low
Fast, Medium, Slow; Tolerates sand and clay.
3–3ft tall , 3–3ft wide
Mar-Aug
Deciduous
Friendly
Interior grasslands and oak woodlands from San Francisco Bay Area to Kern County, 500-4000 ft elevation in dry open areas.
Care Guide
Planting
Plant California Milkweed in full sun where it will get good drainage - it tolerates sand, clay, and even slow-draining soils, so you have flexibility here. This is a Bay Area native, so plant it in spring when soil is workable. Space it where its thick, woolly stems have room to sprawl along the ground, since this plant grows 3 feet tall and likes to spread. Bonus: you're planting a Monarch butterfly host plant that's locally native, which helps the species complete their migration cycle properly.
After Planting
Water regularly the first summer to get it established, then cut back dramatically - once established, it needs maximum 2 waterings per month even in summer. This plant is deciduous and will go dormant, so don't panic when it disappears in winter; it's hardy to 5°F and will return. The #1 mistake Bay Area gardeners make is overwatering this drought-tough native; treat it like the low-water plant it is after year one, and it will thrive for years with minimal fussing.
Visit Calscape for more information about California Milkweed
Endangered & Threatened Species Supported
California Species of Special Concern; monarch populations declining
Wildlife Supported
Insects
Critical larval food plant for multiple generations; essential for spring and fall migration populations
Larval host plant; supports multiple broods throughout warm season
Larval host plant; caterpillars feed on foliage in early summer
Caterpillars feed on milkweed foliage; can reach high densities in late summer