Psorothamnus spinosus
Smoke tree
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Family: Fabaceae · Type: Shrub / Tree · Native
Psorothamnus spinosus (Smoke tree) is a native California shrub / tree in the Fabaceae family, recognized by tree size and leafless appearance.
Smoke tree is a California native shrub found in desert regions of southern California in desert washes at elevations below 400 meters. Flowering from June to July, this plant produces indigo-blue flowers in small clusters with 5 to 15 blossoms. Growing as a distinctive gray-canescent shrub or small tree 1.5 to 8 meters tall, it develops a striking form with branch tips ending in thorns. Its simple leaves are thick and oblanceolate, measuring 0.5 to 2 centimeters long, and typically drop by early summer. The fruit is plump and obovate, gland-dotted, and typically larger than the flower's calyx.
Identification and appearance
Key characters: 6 sympatric species; tree size and leafless appearance are diagnostic
Habitat and range
Habitat: Common. Desert washes
Elevation: < 400 m
California counties: San Bernardino, Riverside, Imperial, San Diego, Calaveras
Outside California: to central Arizona, northwestern Mexico, Baja California
Bloom period
Psorothamnus spinosus blooms Jun-Jul(Oct--Nov).
How to tell it apart
vs Psorodendron: Psorothamnus has gland-dotted surfaces and indigo-purple flowers; Psorodendron has smooth surfaces and yellow flowers.; vs Astragalus: Psorothamnus has gland-dotted surfaces and single-seeded pods; Astragalus has smooth surfaces and multi-seeded inflated pods.; vs Dalea: Psorothamnus has petals arising from flower base; Dalea has petals arising from a fused stamen column.; vs Condea: Psorothamnus has pea-shaped flowers; Condea has two-lipped tubular flowers (mint family).; vs Scutellaria: Psorothamnus has pea-shaped flowers; Scutellaria has hooded two-lipped flowers (mint family).
Frequently asked questions
Is Psorothamnus spinosus native to California?
Yes. Psorothamnus spinosus is native to California (recorded as native).
When does Psorothamnus spinosus bloom?
Psorothamnus spinosus blooms Jun-Jul(Oct--Nov).
Where in California does Psorothamnus spinosus grow?
Psorothamnus spinosus occurs in San Bernardino, Riverside, Imperial, San Diego, Calaveras, at elevations of < 400 m.
What plant family does Psorothamnus spinosus belong to?
Psorothamnus spinosus is in the Fabaceae family, genus Psorothamnus.
What habitat does Psorothamnus spinosus grow in?
Psorothamnus spinosus grows in Common. Desert washes.
Related species
Other California species in the same genus, family, or bioregion.
- Psorothamnus arborescens — Mojave indigo-bush
- Psorothamnus arborescens var. arborescens — Mojave indigo bush
- Psorothamnus arborescens var. californicus — California indigo bush
- Psorothamnus arborescens var. minutifolius — Johnson's indigobush
- Psorothamnus emoryi — Dyebush
- Psorothamnus fremontii — Fremont's dalea
- Robinia neomexicana — New mexico locust
- Robinia pseudoacacia — Black locust
- Robinia sp. — Locust
- Rupertia hallii — Hall's rupertia
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.