Artemisia biennis
Biennial wormwood, Biennial Wormwood
(c) Matt Lavin, some rights reserved (CC BY-SA) · licence
Family: Asteraceae · Type: Herb · Not Native
Artemisia biennis (Biennial wormwood) is a non-native California herb in the Asteraceae family, recognized by annual habit and green unscented nature distinguish from perennial mugwort.
Biennial wormwood is a naturalized annual found in northern coastal California, the Great Valley, central western California, southern California coastal areas, western Transverse Ranges, San Bernardino Mountains, Great Basin, and desert mountains at elevations below 2,200 meters in disturbed moist sites. Flowering from July to November, this plant produces small green flower heads approximately 2 to 4 millimeters in diameter, arranged in dense panicle-like clusters. Growing 30 to 200 centimeters tall with a single erect stem that is often reddish and finely striated, it develops a distinctive branching structure. Its leaves are widely lanceolate, 4 to 13 centimeters long and intricately 2-pinnately divided with sharply toothed lobes. Each plant contains both pistillate and disk flowers, with 6 to 25 pistillate flowers and 15 to 40 disk flowers per cluster.
Identification and appearance
Key characters: 21 sympatric species; annual habit and green unscented nature distinguish from perennial mugwort
Habitat and range
Habitat: Disturbed moist sites
Elevation: < 2200 m
Outside California: North America, native to Europe
Bloom period
Artemisia biennis blooms Jul-Nov.
How to tell it apart
vs Salvia: Artemisia has tiny clustered flower heads in the sunflower family; Salvia has two-lipped tubular flowers in the mint family with square stems.; vs Ambrosia: Artemisia has fused anthers and typically silvery foliage; Ambrosia has free anthers and often deeply lobed green leaves.; vs Ericameria: Artemisia is aromatic with inconspicuous greenish heads lacking rays; Ericameria has bright yellow daisy-like heads with showy ray petals.; vs Pseudognaphalium: Artemisia has no seed bristles and woody stems; Pseudognaphalium has fluffy white pappus bristles and soft herbaceous stems.; vs Eschscholzia: Artemisia has tiny greenish clustered flower heads; Eschscholzia has large showy orange or yellow poppy flowers with 4 petals.
Frequently asked questions
Is Artemisia biennis native to California?
No. Artemisia biennis is not native to California (recorded as not native).
When does Artemisia biennis bloom?
Artemisia biennis blooms Jul-Nov.
What plant family does Artemisia biennis belong to?
Artemisia biennis is in the Asteraceae family, genus Artemisia.
What habitat does Artemisia biennis grow in?
Artemisia biennis grows in Disturbed moist 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.