Heuchera pilosissima
Alum root
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Family: Saxifragaceae · Type: Herb · Native
Heuchera pilosissima (Alum root) is a native California herb in the Saxifragaceae family, recognized by coastal habitat and densely hairy flowers somewhat distinctive.
Alum root is a California native perennial found in coastal bioregions including the northern Coast, central Coast, southern Coast Ranges, and western Transverse Ranges in the Santa Ynez Mountains, growing on ocean bluffs and shaded slopes at elevations below 500 meters. Flowering from March to June, this plant produces delicate white to pink flowers in dense clusters with petals 2 to 3 millimeters long. Growing 15 to 55 centimeters tall with glandular stems, it has an upright, clustered growth habit. Its leaves are distinctively large, with petioles 7 to 20 centimeters long and blades 45 to 90 millimeters wide, generally ovate and deeply divided into 5 to 7 lobes. The flower's calyx lobes are pink to red, creating a subtle and intricate botanical display.
Identification and appearance
Key characters: 2 sympatric species; coastal habitat and densely hairy flowers somewhat distinctive
Habitat and range
Habitat: Ocean bluffs, shaded slopes
Elevation: < 500 m
California counties: Mendocino, Monterey, San Francisco, San Mateo, Santa Barbara, Marin, Sonoma, San Luis Obispo, San Benito, Trinity, Del Norte, Alameda, Santa Cruz, San Bernardino
Bloom period
Heuchera pilosissima blooms Mar-Jun.
How to tell it apart
vs Tellima: Heuchera has branched flower clusters; Tellima's flowers are in a simple unbranched spike; vs Tiarella: Heuchera's flower clusters branch repeatedly; Tiarella has a single bottlebrush-like spike; vs Antigonon: Heuchera has tiny 5-petaled flowers in airy clusters; Antigonon has showy pink heart-shaped sepals on vines; vs Pelargonium: Heuchera has tiny flowers in delicate branched clusters; Pelargonium has large showy flowers with spurred blooms; vs Ribes: Heuchera is herbaceous with basal leaves; Ribes is a woody shrub with maple-like leaves
Frequently asked questions
Is Heuchera pilosissima native to California?
Yes. Heuchera pilosissima is native to California (recorded as native).
When does Heuchera pilosissima bloom?
Heuchera pilosissima blooms Mar-Jun.
Where in California does Heuchera pilosissima grow?
Heuchera pilosissima occurs in Mendocino, Monterey, San Francisco, San Mateo, Santa Barbara, Marin, Sonoma, San Luis Obispo and other counties, at elevations of < 500 m.
What plant family does Heuchera pilosissima belong to?
Heuchera pilosissima is in the Saxifragaceae family, genus Heuchera.
What habitat does Heuchera pilosissima grow in?
Heuchera pilosissima grows in Ocean bluffs, shaded slopes.
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.