Asclepias fascicularis
Narrow-leaf milkweed, Narrow-Leaf Milkweed
Photo by Chez Brungraber
Family: Apocynaceae · Type: Herb · Native
Asclepias fascicularis (Narrow-leaf milkweed) is a native California herb in the Apocynaceae family, recognized by distinctive whorled narrow leaves and prominent exserted horns.
Narrow-leaf milkweed is a California native perennial found in valleys and foothills throughout most of California except the northern coastal and central coastal regions, at elevations of 50 to 2,200 meters. Flowering from May to October, this plant produces white to green-white flowers with purple-tinged petals and distinctive elevated green-white hoods. Growing with ascending to erect stems, it forms clusters of narrow-lanceolate leaves often arranged in whorls of 3 to 5, with smaller leaf clusters developing in axils. Its leaves are narrow and tapered at the base, typically arranged opposite on the stem or in whorled patterns. The plant produces erect fruits containing seeds 5.5 to 7 millimeters long, with distinctive horn-like structures extending beyond the flower hoods.
Identification and appearance
Key characters: 14 sympatric species; distinctive whorled narrow leaves and prominent exserted horns
Habitat and range
Habitat: dry ground, valleys, foothills
Elevation: 50-2200 m
California counties: San Diego, Lake, Kern, San Bernardino, Los Angeles, Fresno, Plumas, Tulare, Riverside, San Mateo, Santa Barbara, Inyo, San Luis Obispo, Orange, Santa Clara, Monterey, Humboldt, Siskiyou, Ventura, Contra Costa, Calaveras, Santa Cruz, Alameda, Mariposa, Sonoma, Mendocino, San Joaquin, Amador, El Dorado, Tuolumne, Placer, Colusa, Modoc, Mono, Lassen, Merced, Yolo, Shasta, Butte, Madera, Stanislaus, Yuba, Sacramento, Alpine, Marin, Trinity, Solano, Kings, Tehama, Sutter, Sierra, Napa, Nevada, Glenn, San Benito
Outside California: to Washington, Utah, Baja California
Bloom period
Asclepias fascicularis blooms May-Oct.
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 fascicularis native to California?
Yes. Asclepias fascicularis is native to California (recorded as native).
When does Asclepias fascicularis bloom?
Asclepias fascicularis blooms May-Oct.
Where in California does Asclepias fascicularis grow?
Asclepias fascicularis occurs in San Diego, Lake, Kern, San Bernardino, Los Angeles, Fresno, Plumas, Tulare and other counties, at elevations of 50-2200 m.
What plant family does Asclepias fascicularis belong to?
Asclepias fascicularis is in the Apocynaceae family, genus Asclepias.
What habitat does Asclepias fascicularis grow in?
Asclepias fascicularis grows in dry ground, valleys, foothills.
Related species
Other California species in the same genus, family, or bioregion.
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.