Crocanthemum aldersonii
Alderson's rush-rose, Alderson's Rush-Rose
(c) Madeleine Claire, some rights reserved (CC BY) · licence
Family: Cistaceae · Type: Perennial · Native
Crocanthemum aldersonii (Alderson's rush-rose) is a native California perennial in the Cistaceae family, recognized by Co-occurs with 3 other taxa; differentiated by larger stature and flower size.
Alderson's rush-rose is a California native perennial found in the southern California coastal and Peninsular Ranges in chaparral slopes and canyons at elevations of 100 to 1,200 meters. Flowering from March to June, this plant produces yellow flowers with delicate obovate petals 8 to 12 millimeters long. Growing with slender stems 30 to 65 centimeters tall, it forms an open, graceful habit with multiple branching stems. Its leaves are narrow and small, with blades 10 to 21 millimeters long and less than 2 millimeters wide, attached to very short petioles. The plant produces distinctive fruits approximately 3.5 to 4 millimeters long, containing small seeds 7 to 12 millimeters in size.
Identification and appearance
Key characters: Co-occurs with 3 other taxa; differentiated by larger stature and flower size
Habitat and range
Habitat: Slopes, canyons in chaparral
Elevation: 100-1200 m
California counties: San Bernardino, San Diego, Riverside, Orange
Outside California: northern Baja California
Bloom period
Crocanthemum aldersonii blooms Mar-Jun.
How to tell it apart
vs Helianthemum: Crocanthemum has alternate stem leaves; Helianthemum has opposite stem leaves.; vs Acmispon: Acmispon has compound leaves with 3-5 leaflets and pea-shaped flowers; Crocanthemum has simple leaves and flat 5-petaled flowers.; vs Dendromecon: Dendromecon is a large shrub with leathery gray-green leaves; Crocanthemum is a ground-hugging herb.; vs Oenothera: Oenothera flowers have 4 petals and an X-shaped stigma; Crocanthemum has 5 petals.; vs Eschscholzia: Eschscholzia has finely dissected ferny leaves; Crocanthemum has simple entire leaves.
Frequently asked questions
Is Crocanthemum aldersonii native to California?
Yes. Crocanthemum aldersonii is native to California (recorded as native).
When does Crocanthemum aldersonii bloom?
Crocanthemum aldersonii blooms Mar-Jun.
Where in California does Crocanthemum aldersonii grow?
Crocanthemum aldersonii occurs in San Bernardino, San Diego, Riverside, Orange, at elevations of 100-1200 m.
What plant family does Crocanthemum aldersonii belong to?
Crocanthemum aldersonii is in the Cistaceae family, genus Crocanthemum.
What habitat does Crocanthemum aldersonii grow in?
Crocanthemum aldersonii grows in Slopes, canyons in chaparral.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-08
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.