Sidalcea robusta
Butte county checkerbloom, Butte County Checkerbloom
Family: Malvaceae · Type: Herb · Native
Conservation status: CNPS 1B.2
Sidalcea robusta (Butte county checkerbloom) is a native California herb in the Malvaceae family, recognized by exceptional height, glaucous appearance, and large pale flowers.
Butte county checkerbloom is a rare (CNPS 1B.2) California native perennial found in southern Cascade Range Foothills and northern Sierra Nevada Foothills near Chico, Butte County in dry banks of chaparral and blue-oak woodland transition at elevations of 100 to 400 meters. Flowering from April to June, this plant produces pale pink flowers with soft yellow tones that are 2 to 3.5 centimeters long. Growing 8 to 12 centimeters tall with clustered, generally unbranched stems that are densely fine-haired at the base, the plant has a distinctive rhizomatous root system. Its leaves are complex, with 5 to 7 deeply toothed lobes that are sparsely stellate-hairy and glaucous, presenting a soft blue-green appearance. The fruit segments are 3 to 3.5 millimeters long with narrow wings and weakly net-veined surfaces.
Identification and appearance
Key characters: 11 sympatric species; exceptional height, glaucous appearance, and large pale flowers
Habitat and range
Habitat: dry banks in chaparral/blue-oak woodland transition
Elevation: 100-400 m
California counties: Butte, Tehama
Bloom period
Sidalcea robusta blooms Apr-Jun.
Conservation status
CNPS 1B.2
How to tell it apart
vs Malva: Sidalcea has no bract ring below flowers and anthers in two circles; Malva has 3 bracts and scattered anthers.; vs Clarkia: Sidalcea has mallow flowers with fused stamens; Clarkia has 4 separate petals and 8 separate stamens.; vs Geranium: Sidalcea has bowl-shaped flowers with fused stamens; Geranium has 5 separate petals and long beaked fruits.; vs Malacothamnus: Sidalcea is herbaceous in meadows; Malacothamnus is a woody shrub in chaparral.; vs Calochortus: Sidalcea is a dicot with 5-petaled flowers; Calochortus is a monocot with 3-petaled flowers from bulbs.
Frequently asked questions
Is Sidalcea robusta native to California?
Yes. Sidalcea robusta is native to California (recorded as native).
When does Sidalcea robusta bloom?
Sidalcea robusta blooms Apr-Jun.
Where in California does Sidalcea robusta grow?
Sidalcea robusta occurs in Butte, Tehama, at elevations of 100-400 m.
What plant family does Sidalcea robusta belong to?
Sidalcea robusta is in the Malvaceae family, genus Sidalcea.
Is Sidalcea robusta rare or endangered?
Sidalcea robusta carries California Rare Plant Rank 1B.2, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · CalPhotos · CDFW CNDDB
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.