Sidalcea hartwegii
Hartweg's checkerbloom
(c) Ken-ichi Ueda, some rights reserved (CC BY), uploaded by Ken-ichi Ueda · licence
Family: Malvaceae · Type: Herb · Native
Sidalcea hartwegii (Hartweg's checkerbloom) is a native California herb in the Malvaceae family, recognized by annual habit and low elevation.
Hartweg's checkerbloom is a California native annual found in northern California regions including the Cache Range, Sierra Nevada foothills, Sacramento Valley, and San Joaquin Valley (eastern Merced County) on dry grassy hillsides and foothill woodlands, often on serpentine soils at elevations below 600 meters. Flowering from April to June, this plant produces rose-purple flowers 18 to 20 millimeters long in small clusters of 4 to 6 blooms. Growing with slender stems 15 to 40 centimeters tall that are slightly hairy at the base, it develops delicate stems with sparse stellate hairs. Its lower leaves have 5 to 7 narrow linear lobes, creating a fine, intricate leaf structure. The fruit segments are 2.5 to 4 millimeters long with smooth sides and a distinctive net-veined, pitted back surface.
Identification and appearance
Key characters: 15 sympatric species - distinguished by annual habit and low elevation
Habitat and range
Habitat: dry grassy hillsides, foothill woodland, often serpentine
Elevation: < 600 m
California counties: Amador, El Dorado, Placer, Butte, Nevada, Lake, Napa, Mendocino, Solano, Tuolumne, Plumas, Siskiyou, Calaveras, Madera, Glenn, Sacramento, Shasta, Sonoma, Merced, Kern, Tehama, Tulare, Sutter, Mariposa, Yuba, Colusa, Stanislaus, Del Norte
Bloom period
Sidalcea hartwegii blooms Apr-Jun.
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 hartwegii native to California?
Yes. Sidalcea hartwegii is native to California (recorded as native).
When does Sidalcea hartwegii bloom?
Sidalcea hartwegii blooms Apr-Jun.
Where in California does Sidalcea hartwegii grow?
Sidalcea hartwegii occurs in Amador, El Dorado, Placer, Butte, Nevada, Lake, Napa, Mendocino and other counties, at elevations of < 600 m.
What plant family does Sidalcea hartwegii belong to?
Sidalcea hartwegii is in the Malvaceae family, genus Sidalcea.
What habitat does Sidalcea hartwegii grow in?
Sidalcea hartwegii grows in dry grassy hillsides, foothill woodland, often serpentine.
Related species
Other California species in the same genus, family, or bioregion.
- Sidalcea hickmanii — Chaparral checkerbloom
- Sidalcea hickmanii subsp. anomala — Cuesta pass checkerbloom
- Sidalcea hickmanii subsp. hickmanii — Hickman's checkerbloom
- Sidalcea hickmanii subsp. napensis — Napa checkerbloom
- Sidalcea hickmanii subsp. parishii — Parish's checkerbloom
- Sidalcea hickmanii subsp. pillsburiensis — Lake pillsbury checkerbloom
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.