Boechera johnstonii
Johnston's rockcress
(c) Matt Berger, some rights reserved (CC BY), uploaded by Matt Berger · licence
Family: Brassicaceae · Type: Perennial · Native
Conservation status: CNPS 1B.2
Boechera johnstonii (Johnston's rockcress) is a native California perennial in the Brassicaceae family, recognized by broad fruits and long styles distinctive.
Johnston's rockcress is a rare (CNPS 1B.2) California native perennial found in the Peninsular Ranges in the Cuyamaca Mountains and San Jacinto Mountains, growing in rocky areas, gravelly soil, chaparral, grassland, and open oak and pine woodland at elevations of 1,300 to 1,700 meters. Flowering from February to March, this plant produces purple flowers about 9 to 14 millimeters long with petals 2 to 4 millimeters wide. Growing with slender stems 5 to 20 centimeters tall, it emerges from a woody caudex with stems bearing short-stalked, 4 to 10-rayed hairs. Its basal leaves are 1.5 to 4 millimeters wide, entire, with short-stalked hairs, while cauline leaves are sparse and become progressively smaller up the stem. The fruit develops as a spreading-ascending silique 4 to 6 centimeters long, containing 26 to 34 seeds arranged in a single row.
Identification and appearance
Key characters: 5 sympatric species; broad fruits and long styles distinctive
Habitat and range
Habitat: Rocky areas, gravelly soil, in chaparral, grassland, open oak/pine woodland
Elevation: 1300-1700 m
California counties: Riverside, San Diego
Bloom period
Boechera johnstonii blooms Feb-Mar.
Conservation status
CNPS 1B.2
How to tell it apart
vs Arabis: Boechera pods hang downward or curve and are wider (2mm+); Arabis pods stand rigidly erect and are narrower.; vs Matthiola: Boechera has flattened pods; Matthiola has cylindrical pods and densely hairy gray-green foliage.; vs Streptanthus: Boechera petals narrow gradually without a claw; Streptanthus petals have a distinct narrow claw at base.; vs Penstemon: Boechera has four-petaled flowers and seed pods; Penstemon has tubular five-lobed flowers.; vs Caulanthus: Boechera is perennial with a woody base; Caulanthus is typically annual or biennial without a woody caudex.
Frequently asked questions
Is Boechera johnstonii native to California?
Yes. Boechera johnstonii is native to California (recorded as native).
When does Boechera johnstonii bloom?
Boechera johnstonii blooms Feb-Mar.
Where in California does Boechera johnstonii grow?
Boechera johnstonii occurs in Riverside, San Diego, at elevations of 1300-1700 m.
What plant family does Boechera johnstonii belong to?
Boechera johnstonii is in the Brassicaceae family, genus Boechera.
Is Boechera johnstonii rare or endangered?
Boechera johnstonii carries California Rare Plant Rank 1B.2, state rank S1.
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 2026-09-30
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.