Ambrosia ambrosioides
Big bur-sage, Big Bur-Sage
(c) Bill Levine, some rights reserved (CC BY), uploaded by Bill Levine · licence
Family: Asteraceae · Type: Shrub · Native
Ambrosia ambrosioides (Big bur-sage) is a native California shrub in the Asteraceae family, recognized by largest burs and leaves in the genus.
Big bur-sage is a California native shrub found in southern Southern California Coast near San Diego in coastal scrub and disturbed sites at elevations below 150 meters. Flowering from March to May, this plant produces small flowers in dense raceme-like clusters, with distinctive staminate and pistillate heads. Growing up to 2.5 meters tall with dark green, coarsely hairy stems that are sticky and aromatic, it has a distinctive bushy appearance. Its large leaves are lance-triangular, 3 to 20 centimeters long, with coarse teeth and a deep green color. The fruit is a remarkable bur 10 to 15 millimeters long, covered in over 50 spiraled, hooked spines that give the plant its distinctive "bur" character.
Identification and appearance
Key characters: 11 sympatric species; largest burs and leaves in the genus
Habitat and range
Habitat: Coastal scrub, disturbed sites
Elevation: < 150 m
Outside California: Arizona, northwestern Mexico
Bloom period
Ambrosia ambrosioides blooms Mar-May.
How to tell it apart
vs Artemisia: Ambrosia produces spiny burs as fruits; Artemisia has tiny dry fruits without spines and strongly aromatic foliage.; vs Atriplex: Ambrosia has flower heads in spikes producing spiny burs; Atriplex has inconspicuous flowers with papery bracts and scurfy gray foliage.; vs Baccharis: Ambrosia has both male and female flowers on the same plant; Baccharis has male and female flowers on separate plants.; vs Eriogonum: Ambrosia has greenish flower heads producing spiny burs; Eriogonum has showy clusters of white, pink, or yellow flowers with papery bracts.; vs Salvia: Ambrosia has inconspicuous greenish flowers in the Asteraceae; Salvia has showy tubular lipped flowers typical of mints.
Frequently asked questions
Is Ambrosia ambrosioides native to California?
Yes. Ambrosia ambrosioides is native to California (recorded as native).
When does Ambrosia ambrosioides bloom?
Ambrosia ambrosioides blooms Mar-May.
What plant family does Ambrosia ambrosioides belong to?
Ambrosia ambrosioides is in the Asteraceae family, genus Ambrosia.
What habitat does Ambrosia ambrosioides grow in?
Ambrosia ambrosioides grows in Coastal scrub, disturbed sites.
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.