Asclepias speciosa
Showy milkweed
(c) Peter L Achuff, some rights reserved (CC BY), uploaded by Peter L Achuff · licence
Family: Apocynaceae · Type: Herb · Native
Asclepias speciosa (Showy milkweed) is a native California herb in the Apocynaceae family, recognized by distinctive large rose-purple flowers with prominent pink hoods.
Showy milkweed is a California native perennial found in various bioregions across California, inhabiting fields, roadsides, and diverse habitats at elevations up to 1,900 meters. Flowering from May to September, this plant produces rose-purple flowers with distinctive pink aging to yellow hood-like structures that dramatically extend above the corolla base. Growing with ascending to erect hairy stems, it develops opposite leaves that are elliptic to ovate and often clasp the stem. Its leaves have short petioles and range from 5 to 15 centimeters long, with a base that occasionally appears heart-shaped. The plant produces erect fruits containing seeds 6 to 9 millimeters long, making it a critical habitat plant for monarch butterflies.
Identification and appearance
Key characters: 14 sympatric species; distinctive large rose-purple flowers with prominent pink hoods
Habitat and range
Habitat: Many habitats including fields, roadsides
Elevation: < 1900 m
California counties: Inyo, Humboldt, Sacramento, Amador, Plumas, Lake, Trinity, Fresno, Siskiyou, Calaveras, Modoc, Nevada, Yolo, Tuolumne, Tulare, Mono, Mariposa, Mendocino, Los Angeles, Shasta, Lassen, Butte, San Joaquin, El Dorado, Marin, Placer, Del Norte, Sierra, Yuba, Colusa, Tehama, Solano, Glenn, Alpine, Napa, Madera, Sutter
Outside California: to western Canada, Texas
Bloom period
Asclepias speciosa blooms May-Sep.
How to tell it apart
vs Gomphocarpus: Asclepias has hoods that touch or nearly touch at their edges; Gomphocarpus has gaps between hood edges.; vs Erigeron: Asclepias has rounded umbel clusters with large individual flowers; Erigeron has daisy-like flowers with many thin ray petals.; vs Lantana: Asclepias has reflexed petals with a raised hood crown; Lantana has flat-faced tubular flowers in dense rounded heads.; vs Apocynum: Asclepias has large showy flowers in dome-shaped clusters; Apocynum has tiny bell-shaped flowers in branched sprays.; vs Baccharis: Asclepias has milky sap and large distinctive flowers; Baccharis has clear sap and tiny fuzzy composite flowers.
Frequently asked questions
Is Asclepias speciosa native to California?
Yes. Asclepias speciosa is native to California (recorded as native).
When does Asclepias speciosa bloom?
Asclepias speciosa blooms May-Sep.
Where in California does Asclepias speciosa grow?
Asclepias speciosa occurs in Inyo, Humboldt, Sacramento, Amador, Plumas, Lake, Trinity, Fresno and other counties, at elevations of < 1900 m.
What plant family does Asclepias speciosa belong to?
Asclepias speciosa is in the Apocynaceae family, genus Asclepias.
What habitat does Asclepias speciosa grow in?
Asclepias speciosa grows in Many habitats including fields, roadsides.
Related species
Other California species in the same genus, family, or bioregion.
- Asclepias subulata — Rush milkweed
- Asclepias vestita — Woolly milkweed
- Asclepias albicans — White-stemmed milkweed
- Asclepias asperula subsp. asperula — Antelope-horns
- Asclepias californica — California milkweed
- Asclepias cordifolia — Purple milkweed
- Catharanthus roseus — Madagascar periwinkle
- Catharanthus sp.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.