Cistus psilosepalus
Rock rose
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Family: Cistaceae · Type: Shrub · Not Native
Cistus psilosepalus (Rock rose) is a non-native California shrub in the Cistaceae family, recognized by sepal shape and leaf margin characters diagnostic but subtle.
Rock rose is a naturalized shrub found in the central Coast and San Francisco Bay regions in disturbed urban places at elevations below 300 meters. Flowering from May to October, this plant produces white petals 1 to 1.5 centimeters long in compact clusters. Growing up to 1 meter tall with stems covered in both glandular and nonglandular hairs, the plant has a distinctive appearance. Its leaves are sessile, ranging from linear to ovate-oblong, 20 to 70 millimeters long, with wrinkled surfaces and three main veins emerging from the base. The fruit develops with five distinctive valves, contributing to its unique botanical structure.
Identification and appearance
Key characters: 3 sympatric species; sepal shape and leaf margin characters diagnostic but subtle
Habitat and range
Habitat: Uncommon. Disturbed places
Elevation: < 300 m
Outside California: native to southwestern Europe
Bloom period
Cistus psilosepalus blooms May-Oct.
How to tell it apart
vs Rosa: Cistus petals have no notch and leaves lack stipules; Rosa petals are notched and have leafy stipules at leaf base.; vs Carpenteria: Cistus has 5-12 capsule segments when fruit opens; Carpenteria has 5-7 segments and pointed evergreen leaves.; vs Romneya: Cistus is a shrub with small opposite leaves; Romneya has large divided gray-green leaves and huge white flowers.; vs Salvia: Cistus has 5 separate rounded petals; Salvia has fused tubular flowers with upper and lower lips.; vs Oenothera: Cistus has opposite leaves and 5-12 capsule segments; Oenothera has alternate leaves and 4-celled capsules.
Frequently asked questions
Is Cistus psilosepalus native to California?
No. Cistus psilosepalus is not native to California (recorded as not native).
When does Cistus psilosepalus bloom?
Cistus psilosepalus blooms May-Oct.
What plant family does Cistus psilosepalus belong to?
Cistus psilosepalus is in the Cistaceae family, genus Cistus.
What habitat does Cistus psilosepalus grow in?
Cistus psilosepalus grows in Uncommon. Disturbed places.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CalPhotos
Last updated 2026-04-09
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.